Question: At 9.0 in the morning, a ship departs from point A and sails in the direction due east at a speed of 40.0 nautical miles per hour, and arrives at point B at 9.0 and 30.0 minutes. As shown in the figure, the island M is measured from A and B. In the direction of 45.0 north by east and 15.0 north by east, then the distance between B and island M is ()


Question: In order to measure the width of parallel river AB, angle ACB = 30.0, angle ADB = 60.0, CD = 60.0, then the width of the river AB is ()


Question: As shown in the figure, it is known that a fisherman on a fishing boat sees lighthouse M in the direction 60.0 east by north at point A. This fishing boat sails eastward at a speed of 28.0 nautical miles/hour, and arrives at point B in half an hour, and sees it at point B The lighthouse M is in the 15.0 direction to the east by north. At this time, the distance between the lighthouse M and the fishing boat is ()


Question: As shown in the figure, it is known thatfrac {OA}{DO}=frac {BO}{CO}=frac {1.0}{2.0}, the area of triangle AOB is 100.0 ^ 2, then the area of triangle DOC is ()


Question: As shown in the figure, in triangle ABC, angle BAC = 90.0, AD perpendicular  BC at D, if AB = 3.0, BC = 5.0, then the length of DC ()


Question: As shown in the figure, in the parallelogram ABCD, AE:EB=1.0:2.0,S~triangle AEF~=3.0, then S~triangle FCD~ is ()


Question: As shown in the figure, in the parallelogram ABCD, AE = EB, AF = 2.0, then the value of FC is ()


Question: As shown in the figure, in Rttriangle ABC, angle BAC = 90.0, AD perpendicular  BC at D, DE perpendicular  AB at E, AD = 3.0, DE = 2.0, then the length of CD is ()


Question: As shown in the figure, the known point D is the midpoint of AB, AF parallel  BC, CG:GA=3.0:1.0,BC=8.0, then AF is equal to ()


Question: As shown in the figure, it is known that the radius of circle O is 6.0, M is a point outside circle O, and OM = 12.0, the line passing M and circle O intersect at A and B, the symmetrical points of points A and B with respect to OM are C, D, AD and BC intersect at point P, then the length of OP is ()


Question: As shown in the figure, in parallelogram ABCD, E is the midpoint of CD, AE intersects BD at point O, S~triangle DCE~ = 12.0, then S~triangle AOD~ is equal to ()


Question: As shown in the figure, in triangle ABC, angle ACB = 90.0, D is the point on AB, connect CD, angle ACD = angle B, if BC = 13.0, CD = 5.0, then BD = ()


Question: As shown in the figure, it is known that D and E are the points on AB and AC in triangle ABC, DE parallel  BC and frac {AD}{AB}=frac {1.0}{3.0}, the perimeter of triangle ADE is 2.0, then the perimeter of triangle ABC is ()


Question: As shown in the figure, in triangle ABC, D is a point on AC, if angle DBC = angle A, BC = 3.0, AC = 6.0, then the length of CD is ()


Question: As shown in the figure, DE parallel  BC, BD, CE intersect at O, frac {EO}{OC}=frac {1.0}{3.0}, AE = N_3, then EB = ()


Question: As shown in the figure, a beam of light reflects from point A (-3.0, 3.0), through point C on the y axis, and then passes through point B (-1.0, 0.0), then the length of the path of the light from point A to point B is ()


Question: As shown in the figure, in triangle ABC, if DE parallel  BC, frac {AD}{AB}=frac {1.0}{3.0}, DE = 4.0, then the length of BC is ()


Question: As shown in the figure, it is known that D, E, and F are points on the side BC, CA, and AB of isosceles triangle ABC respectively. If AB = AC, angle FDE = angle B, BD = 2.0, CD = 3.0, CE = 4.0, AE = 1.0, then the length of AF is ()


Question: As shown in the figure, the cross section of a small reservoir dam is a right trapezoid, the width of crest BC is 6.0, the height of dam is 14.0, and the slope of the slope CD is i = 1.0:2.0, then the length of the dam bottom AD is ()


Question: As shown in the figure, the slope of the slope formed by the conveyor belt and the ground is 1.0:2.0, it sends the object from the ground point A to the point B higher than the ground 2.0, then the distance the object travels from A to B is ()


Question: As shown in the figure, in triangle ABC, AB = AC = 18.0, BC = 12.0, the vertices E and F of the square DEFG are in triangle ABC, the vertices D and G are on AB and AC respectively, AD = AG, DG = 6.0, then the distance from point F to BC is ()


Question: As shown in the figure, in the square ABCD with edge length 9.0, F is a point on AB. Connect CF. Pass point F to draw FE perpendicular  CF which intersects AD at point E, if AF = 3.0, then AE is equal to ()


Question: As shown in the figure, in Rttriangle ABC, angle BAC = 90.0, AB = 2.0, AC = 3.0, D is the midpoint of BC, and moving points E and F are on AB and AC respectively, passing points to draw EG parallel  AD parallel  FH, and they intersect BC at points G and H, if EF parallel  BC, then the value of EF + EG + FH is ()


Question: As shown in the figure, in triangle ABC, D and E are points on AB and AC respectively, and DE parallel  BC, if AD = 5.0, DB = 3.0, DE = 4.0, then BC is equal to ()


Question: As shown in the figure, in the parallelogram ABCD, E is the midpoint of DC, the area of triangle DEF is 2.0, then the area of triangle ABF is ()


Question: As shown in the figure, AB parallel  CD, frac {AO}{OD}=frac {2.0}{3.0}, then the ratio of the perimeter of triangle AOB to the perimeter of triangle DOC is ()


Question: As shown in the figure, AB parallel  CD, AC, BD intersect at O, BO = 6.0, DO = 3.0, AC = 12.0, then the length of AO is ()


Question: As shown in the figure, in triangle ABC, E and F are the midpoints of AB and AC respectively. If the area of triangle AEF is 1.0, then the area of the quadrilateral EBCF is ()


Question: As shown in the figure, in the trapezoidal ABCD, AD parallel  BC, diagonal AC, BD intersect at point O, if S~triangle AOD~:S~triangle OCD~ = 1.0:2.0, then S~triangle AOD~:S~triangle BOC~ = ()


Question: As shown in the figure, planting trees on the hillside, it is known that angle A = 30.0, AC = 3.0, the distance of slope AB of two adjacent trees is equal to ()


Question: As shown in the figure, the elevation angle of the top of a building is 30.0 when viewed from point A in the air by a hot air balloon, and the depression angle of this building is 60.0. The horizontal distance between the hot air balloon and the building is 120.0. The height of this building is ()


Question: As shown in the figure, a teaching interest group wants to measure the height of a tree CD. They firstly measured the elevation angle of the tree top C at point A as 30.0, and then proceeded 10.0 along the direction of AD to point B, and the elevation angle of tree top C measured at B is 60.0  (the three points A, B, and D are on the same straight line), then the height of the tree CD is ()


Question: As shown in the figure, in order to measure the height of the TV tower AB, use the goniometer CD with a height of 1.0 at D, and measure the elevation angle of the top A of the TV tower to be 30.0, and then walk 120.0 in the direction of the TV tower to F, and the elevation angle of the top A of the TV tower is 60.0, then the height of this TV tower AB (unit:) is ()


Question: As shown in the figure, in a mathematics extracurricular practice activity, Xiaowen measured the elevation angle of the top A of the tree at point C to be 37.0, BC = 20.0, then the height of the tree AB is () (reference data: sin37° approximate 0.6, cos37° approximate  0.8, tan37° approximate 0.75)


Question: As shown in the figure, to build a highway in a certain place, a tunnel must be built from B to C (B and C are on the same level). In order to measure the distance between B and C, an engineer took a hot air balloon to start from C and rose vertically 100.0 to reach A. Observing the depression angle of B at A is 30.0, then the distance between B and C is ()


Question: In the mathematics practice inquiry class, the teacher arranged for the students to measure the height of the school flagpole. As shown in the figure, Xiao Ming's study group is at a distance of 10.0 from the bottom of the flagpole. The elevation angle of the top of the flagpole is measured with a goniometer as 60.0, then the height of the flagpole is ().


Question: As shown in the figure, to measure the height AB of a tower that cannot be reached at the bottom, two students of A and B took measurements at C and D respectively. Given that the points B, C and D are on the same straight line, and AB perpendicular  BD, CD = 12.0, angle ACB = 60.0, angle ADB = 30.0, the height of the tower AB is ()


Question: As shown in Figure 1, the clock face of a clock is fixed perpendicularly on the horizontal desktop, and there is a point A on the minute hand, and when the clock face displays 3.0 o'clock 30.0 minutes, the minute hand is perpendicular to the desktop, and the height from point A to the desktop is 10.0 cm. As shown in Figure 2, if the clock face displays 3.0 o'clock and 45.0 minutes, and the height of point A from the desktop is 16.0 cm, then the clock face displays 3.0 o'clock and 50.0 minutes, how many centimeters is the height of point A from the desktop ()


Question: As shown in the figure, PA and PB are the tangents of circle O, AC is the diameter of circle O, angle P = 50.0, then the degree of angle BOC is ()


Question: As shown in the figure, in Rttriangle ABC, AD perpendicular  BC at D, DE perpendicular  AB at E, if AD = 3.0, DE = 2.0, then AC = ()


Question: As shown in the figure, in triangle ABC, AB = BC = 2.0, circle O with AB as the diameter is tangent to BC at point B, then AC is equal to ()


Question: Definition: The minimum value of the distance between a fixed point A and any point on circle O is called the distance between point A and circle O. There is a rectangle ABCD (as shown in the figure), AB = 14.0, BC = 12.0, circle K and the edges AB, BC, and CD of the rectangle are respectively tangent to the points E, F, G, then the distance between point A and circle K is ()


Question: As shown in the figure, circle O is the circumscribed circle of triangle ABC, angle BOC = 3.0 angle AOB, if angle ACB = 20.0, then the degree of angle BAC is ()


Question: As shown in the figure, AB is the diameter of circle O, C and D are two points on circle O, CD perpendicular  AB, if angle DAB = 70.0, then angle BOC = ()


Question: As shown in the figure, A, B, and C are all points on circle O, if angle ABC = 110.0, then the degree of angle AOC is ()


Question: Point B is on circle O, point C is a point different from A and B on circle O, if angle AOB = 50.0, then the degree of angle ACB is ()


Question: As shown in the figure, given that points A, B, and C are on circle O, angle AOB = 100.0, then the degree of angle ACB is ()


Question: As shown in the figure, AB is the diameter of circle O, CD is the chord of circle O, angle ABD = 59.0, then angle C is equal to ()


Question: As shown in the figure, in the square ABCD, AB = 8.0, Q is the midpoint of CD, set angle DAQ = α, take a point P on CD, make angle BAP = 2.0 α, then the length of CP is ()


Question: As shown in the figure, the intersection of the two diagonals of the rectangle is 60.0, AC + BD = 20.0, then the length of AB is ()


Question: As shown in the figure, in the diamond ABCD, angle BAD = 120.0, the length of the diagonal AC is 3.0, then the perimeter of the diamond ABCD is ()


Question: As shown in the figure, angle MON = 90.0, moving points A and B are respectively located on the radials OM and ON, the edge AB of the rectangle ABCD = 6.0, BC = 4.0, then the maximum length of the line segment OC is ()


Question: As shown in the figure, in the diamond ABCD, angle BAD = 120.0, BC = 10.0, then the length of the diagonal AC is equal to ()


Question: As shown in the figure, the perimeter of the diamond ABCD is 16.0, angle A = 60.0, then the length of the diagonal BD is ()


Question: As shown in the figure, in the diamond ABCD, AB = 5.0, angle B = 60.0, then the diagonal AC is equal to ()


Question: As shown in the figure, in the diamond ABCD, AB = 15.0, angle ADC = 120.0, then the distance between the two points B and D is ()


Question: As shown in the figure, in the diamond ABCD, two diagonal lines AC = 12.0, BD = 16.0, then the edge length of this diamond is ()


Question: As shown in the figure, in the diamond ABCD, angle BAD = 80.0, the perpendicular bisector of AB intersects the diagonal AC at point F, E is the foot of perpendicular. Connect DF, then angle CDF is equal to ()


Question: As shown in the figure, in the diamond ABCD, angle B = 60.0, AB = 2.0, E and F are the midpoints of BC and CD respectively, connect AE, EF, and AF, then the perimeter of triangle AEF is ()


Question: As shown in the figure, in parallelogram ABCD, BC = BD, angle C = 65.0, then the degree of angle ADB is ()


Question: As shown in the figure, in parallelogram ABCD, AB = 6.0, BC = 8.0, the bisector of angle C intersects AD at E, and intersects the extended line of BA at F, then the value of AE + AF is equal to ()


Question: As shown in the figure, in parallelogram ABCD, AE perpendicular  BC is at E, AF perpendicular  DC and it intersects the extended line of DC at point F, and angle EAF = 60.0, then angle B is equal to ()


Question: As shown in the figure, in parallelogram ABCD, AE bisects angle BAD, if CE = 3.0, AB = 4.0, then the perimeter of parallelogram ABCD is ()


Question: As shown in the figure, in parallelogram ABCD, AE bisects angle BAD, and it is known that angle AEB = 63.0, then the degree of angle D is ()


Question: As shown in the figure, in parallelogram ABCD, the diagonal AC and BD intersect at point O, AC = 10.0, BD = 6.0, AD = 4.0, then the area of parallelogram ABCD is ()


Question: As shown in the figure, the diagonal of the parallelogram ABCD intersects at the point O, and AB = 6.0, the perimeter of triangle OCD is 19.0, then the sum of the two diagonals of parallelogram ABCD is ()


Question: As shown in the figure, in the parallelogram ABCD, if angle B = 60.0, then angle D is equal to ()


Question: As shown in the figure, in the parallelogram ABCD, it is known that angle AOB = 90.0, AC = 8.0, AD = 5.0, then the length of BD is ()


Question: As shown in the figure, in parallelogram ABCD, CE perpendicular  AB, the foot of perpendicular is E, if angle A = 115.0, then angle BCE is equal to ()


Question: As shown in the figure, in the parallelogram ABCD, CE bisects angle BCD and it intersects the AD edge at point E, and DE = 3.0, then the length of AB is ()


Question: In parallelogram ABCD, the diagonal AC and BD intersect at the point O, angle DAC = 42.0, angle CBD = 23.0, then angle COD is ()


Question: As shown in the figure, the diagonals AC and BD of the parallelogram ABCD intersect at point O, point E is the midpoint of CD, and the perimeter of triangle ABD is 16.0, then the perimeter of triangle DOE is ()


Question: As shown in the figure, in parallelogram ABCD, BM is the bisector of angle ABC and it intersects CD at point M, and MC = 2.0, the perimeter of parallelogram ABCD is 14.0, then DM is equal to ()


Question: As shown in the figure, P is a point of parallelogram ABCD. Given that S~triangle ABP~ = 3.0, S~triangle PDC~ = 2.0, then the area of the parallelogram ABCD is ()


Question: As shown in the figure, in parallelogram ABCD, AE bisects angle BAD and it intersects BC at point E. If AD = 8.0, EC = 2.0, then the length of AB is ()


Question: As shown in the figure, in the parallelogram ABCD, the straight line CE perpendicular  AB passing through the point C, the foot of perpendicular is E, if angle EAD = 54.0, then the degree of angle BCE is ()


Question: As shown in the figure, in parallelogram ABCD, BD = CD, angle C = 70.0, AE perpendicular  BD at point E, then the degree of angle BAE is ()


Question: As shown in the figure, P is a point in the parallelogram ABCD, and cross point P to draw the parallel line of AB and AD to intersect the parallelogram at the four points of E, F, G, and H. If S~AHPE~ = 3.0, S~PFCG~ = 5.0 , Then S~triangle PBD~ is ()


Question: As shown in the figure, in parallelogram ABCD, angle A = 120.0, then angle 1 = ()


Question: As shown in the figure, in parallelogram ABCD, CE perpendicular  AB, point E is the foot of perpendicular, if angle D = 55.0, then angle BCE = ()


Question: As shown in the figure, in parallelogram ABCD, angle ABC = 60.0, AB = BC = 4.0, points M and N are on edges BC and CD respectively, and angle MAN = 60.0, then the area of the quadrilateral AMCN is ()


Question: As shown in the figure, in the parallelogram ABCD, AB = 4.0, BC = 6.0, and the perpendicular bisector of AC intersects AD at point E, then the perimeter of triangle CDE is ()


Question: As shown in the figure, in parallelogram ABCD, AD = 3.0, DC = 5.0, and the perpendicular bisector of BD intersects BD at point E, then the perimeter of triangle BCE is ()


Question: As shown in the figure, the perimeter of parallelogram ABCD is 10.0, AC and BD intersect at point O, and OE perpendicular  AC and it intersects AD at E, then the perimeter of triangle DCE is ()


Question: As shown in the figure, in the parallelogram ABCD, it is known that AB = 6.0, BC = 9.0, angle B = 30.0, then the area of the parallelogram ABCD is ()


Question: As shown in the figure, in parallelogram ABCD, angle AEB = 36.0, BE bisectes angle ABC, then angle C is equal to ()


Question: As shown in the figure, the diagonal of the parallelogram ABCD intersects at the point O, and AB = 5.0, the perimeter of triangle OCD is 23.0, then the sum of the two diagonals of the parallelogram ABCD is ()


Question: As shown in the figure, in parallelogram ABCD, the diagonal AC and BD intersect at point O, if AC = 12.0, BD = 8.0, AB = 7.0, then the perimeter of triangle OAB is ()


Question: The perimeter of the parallelogram ABCD is 28.0, AC and BD intersect at point O, the perimeter of triangle AOB is 4.0 larger than the perimeter of triangle OBC, then AB is equal to ()


Question: As shown in the figure, in the parallelogram ABCD, the diagonal AC and BD intersect at point O, and cross O point to draw OE parallel  BC and it intersects DC at point E. If OE = 2.5, then the length of AD is ()


Question: As shown in the figure, the diagonal AC and BD of the parallelogram ABCD intersect at the point O, AB = 7.0, AC = 10.0, the perimeter of triangle ABO is 16.0, then the length of the diagonal BD is equal to ()


Question: As shown in the figure, E is any point in parallelogram ABCD, if S~quadrilateral ABCD~ = 6.0, then the area of the shaded part in the figure is ()


Question: As shown in the figure, in the parallelogram ABCD, AB = 4.0, the bisector of angle BAD and the extended line of BC intersect at point E, and DC at point F, and point F is the midpoint of DC, DG perpendicular  AE, foot of perpendicular is G, if DG = 1.0, then the edge length of AE is ()


Question: As shown in the figure, AB is the chord of circle O, passing point A to draw the tangent AC of circle O. If angle BAC = 55.0, then angle AOB is equal to ()


Question: As shown in the figure, the line segment AB crosses the center O, intersects circle O at points A and C, angle B = 30.0, and the straight line BD and circle O tangent to point D, then the degree of angle ADB is ()


Question: As shown in the figure, in the parallelogram ABCD, AC and BD are diagonals, BC = 6.0, and the height on BC is 4.0, then the area of the shaded part in the figure is ()


Question: As shown in the figure, the parallelogram ABCD is divided into 4.0 parallelograms. It is known that the three areas are 8.0, 10.0, and 30.0, then the area of the fourth parallelogram is ()


Question: As shown in the figure, the diagonal AC and BD of parallelogram ABCD intersect at point O, if AC + BD = 10.0, BC = 4.0, then the perimeter of triangle BOC is ()


Question: As shown in the figure, in parallelogram ABCD, AC and BD intersect at point O, points E and F are on edges AD and BC respectively, and EF passes through point O. If AB = 3.0, BC = 5.0, EF = AB, then the perimeter of the quadrilateral CDEF is ()


Question: As shown in the figure, the perpendicular bisector of the diagonal AC of the parallelogram ABCD and the edges BC and DA intersect at E and F, respectively, and connect CF. If the perimeter of the parallelogram ABCD is equal to 18.0, then the perimeter of triangle CDF is equal to ()


Question: As shown in the figure, in triangle ABC, AB = AC, angle A = 40.0, draw an arc with C as the center and the length of CB as the radius, intersect AB at point D, connect CD, then angle ACD is equal to ()


Question: As shown in the figure, in circle O, it is known that angle AOB = 110.0, C is a point on the circle, then angle ACB is ()


Question: As shown in the figure, CD is the diameter of circle O, chord DE parallel  OA, if the degree of angle D is 50.0, then the degree of angle C is ()


Question: As shown in the figure, BD is the diameter of circle O, points A and C are on circle O, and BD perpendicular  AC, if the degree of arc AB is 60.0, then the degree of angle BDC is ()


Question: As shown in the figure, it is known that AB and AD are the chords of circle O, angle B = 20.0, point C is on chord AB, connect CO and extend CO to intersect circle O at point D, angle D = 15.0, then the degree of angle BAD is ()


Question: As shown in the figure, circle O is the circumscribed circle of triangle ABC, and it is known that angle C = 60.0, then the degree of angle BAO is ()


Question: As shown in the figure, AB is the diameter of the semicircle, angle ABC = 50.0, point D is the midpoint of arc AC, then angle DAB is equal to ()


Question: As shown in the figure, AB is the diameter of circle O, the chord CD and AB intersect, and angle ABC = 32.0, then the degree of angle CDB is ()


Question: As shown in the figure, arc AB is a semicircle. Connect AB, point O is the midpoint of AB, points C and D are on arc AB, connecting AD, CO, BC, BD, OD. If angle COD = 62.0 and AD parallel  OC, then the size of angle ABD is ()


Question: As shown in the figure, AB is the diameter of circle O, point C and point D are on circle O. Connect AC, BC, AD, CD, if angle BAC = 50.0, then the degree of angle ADC is equal to ()


Question: As shown in the figure, AB is the diameter of circle O, angle AOC = 140.0, then angle D is ()


Question: As shown in the figure, in circle O, the diameter AB perpendicular  chord CD at point H, E is the point on circle O, if angle BEC = 25.0, then the degree of angle BAD is ()


Question: As shown in the figure, AB is the diameter of circle O, CD is the chord of circle O, angle ABD = 53.0, then angle BCD is ()


Question: As shown in the figure, circle O is the circumscribed circle of triangle ABC, angle AOB = 60.0, then the degree of angle C is ()


Question: As shown in the figure, points A, B, and C are three points on circle O, angle AOC = 110.0, then angle ABC is equal to ()


Question: As shown in the figure, AB is the diameter of circle O, CD is the chord, and AB perpendicular  CD, the foot of perpendicular is the point E, it is known that angle COB = 60.0, then the degree of angle DAB is ()


Question: As shown in the figure, it is known that AB is the diameter of circle O, if the degree of angle BOC is 50.0, then the degree of angle A is ()


Question: As shown in the figure, points A, B, and C are on circle O, angle AOB = 140.0, and the degree of angle ACB is ()


Question: As shown in the figure, AB is the diameter of circle O, CD is a chord of circle O, and CD perpendicular  AB at E, respectively connect AD and BC, it is known that angle D = 65.0, then angle OCD = ()


Question: As shown in the figure, AB is the diameter of circle O, CD is the chord of circle O, angle ACD = 42.0, then angle BAD = ().


Question: As shown in the figure, AB is the diameter of circle O, angle AOC = 110.0, then angle D = ()


Question: As shown in the figure, AB is the diameter of circle O, point C is on circle O, if angle ABC = 30.0, then angle CAB is ()


Question: As shown in the figure, P is a point outside circle O, PA and PB intersect circle O at two points C and D respectively. It is known that the central angles of arc AB and arc CD are 90.0 and 50.0 respectively, then angle P = ()


Question: As shown in the figure, given that the three points A, B and C are on circle O, AC perpendicular  BO at D, angle B = 50.0, then the degree of angle BOC is ()


Question: As shown in the figure, in circle O, the length of chord AB is 2.0, OC perpendicular  AB at C, OC = 1.0, if two tangents of circle O are drawn from a point P outside circle O, the tangent points are A and B respectively, then angle APB The degree is ()


Question: As shown in the figure, in triangle ABC, AB = 10.0, AC = 8.0, BC = 6.0, the moving circle passing through point C and tangent to edge AB intersects CA and CB at points P and Q respectively, then the minimum value of the length of the line segment PQ is ()


Question: As shown in the figure, in triangle ABC, AB = 2.0, AC = 1.0, the circle with AB as the diameter is tangent to AC and intersects the edge BC at point D, then the length of AD is ()


Question: As shown in the figure, AB is the diameter of circle O, point C is on the extended line of AB, CD is tangent to circle O, and the tangent point is D. If angle A = 35.0, then angle C is equal to ()


Question: As shown in the figure, in Rttriangle ABC, angle ACB = 90.0, AC = 4.0, BC = 3.0, the circle with AC as the diameter intersects AB at D, then the length of AD is ()


Question: As shown in the figure, it is known that AD and BC intersect at point O, AB parallel  CD, if angle B = 40.0, angle D = 30.0, then the size of angle AOC is ()


Question: As shown in the figure, in triangle ABC, AB = AC, D is the midpoint of BC, angle B = 40.0, then angle BAD = ()


Question: As shown in the figure, angle A = 70.0, angle 2 = 130.0, then angle 1 = ()


Question: As shown in the figure, in the quadrilateral ABCD, angle BAD = 120.0, angle B = angle D = 90.0, if you find a point M on BC and CD respectively, so that the perimeter of triangle AMN is the smallest, then the degree of angle AMN + angle ANM is ()


Question: As shown in the figure, fold the rectangle ABCD along the line segment OG to the position of OB'C'G, angle OGC' is equal to 100.0, then the degree of angle DGC' is ()


Question: As shown in the figure, AB is the diameter of circle O, if angle BDC = 40.0, then the degree of angle BOC is ()


Question: As shown in the figure, fold triangle ABC so that point A coincides with point D at BC, and the crease is MN. If AB = 9.0, BC = 6.0, then the perimeter of triangle DNB is ()


Question: As shown in the figure, the perimeter of parallelogram ABCD is 36.0, the diagonal AC and BD intersect at point O, point E is the midpoint of CD, BD = 12.0, then the perimeter of triangle DOE is ()


Question: As shown in the figure, points A, B, C, D are on circle O, angle AOC = 140.0, point B is the midpoint of arc AC, then the degree of angle D is ()


Question: As shown in the figure, AB is the diameter of circle O, and points C and D are on circle O. If angle ABD = 50.0, then the degree of angle BCD is ()


Question: As shown in the figure, in triangle ABC, angle CAB = 30.0, rotate triangle ABC anticlockwise in the plane around point A to the position of triangle AB'C', and CC' parallel  AB, then the degree of rotation angle is ()


Question: As shown in the figure, O is a point on the straight line AB, angle 1 = 40.0, OD bisects angle BOC, then the degree of angle 2 is ()


Question: As shown in the picture, it is a beautiful Pythagorean tree, in which all quadrilaterals are squares, and all triangles are right triangles. The areas of square A, B, C, and D are 2.0, 5.0, 1.0, 2.0, respectively. Then the area of the largest square E is ().


Question: As shown in the figure, the straight lines AB and CD are cut by BC. If AB parallel  CD, angle 1 = 45.0, angle 2 = 35.0, then angle 3 = ()


Question: As shown in the figure, in Rttriangle ABC, angle BAC = 90.0, rotate triangle ABC clockwise around point A by 90.0 to obtain triangle AB′C′ (the corresponding point of point B is point B′, and the corresponding point of point C is point C ′), connect CC′. If angle CC′B′ = 32.0, then the size of angle AC′B′ is ()


Question: Known: As shown in the figure, AB parallel  CD, BC bisects angle ABD, and angle C = 40.0, then the degree of angle D is ()


Question: Given that the straight line a parallel  b, angle 1 and angle 2 are mutually complementary, angle 3 = 121.0, then angle 4 is equal to ()


Question: In triangle ABC, AB = AC, D and E are respectively on BC and AC, AD = AE, angle CDE = 20.0, then the degree of angle BAD is ()


Question: As shown in the figure, the vertex A of the line parallel  n, Rttriangle ABC is on the line n, angle C = 90.0, AB, CB intersect the line at point D and point E respectively, and DB = DE, if angle B = 25.0, then the degree of angle 1 is ()


Question: As shown in the figure, the straight line a parallel  b, the straight line c and the straight lines a, b intersect at the points A, B, AM perpendicular  b, and the foot of perpendicular is the point M. If angle 1 = 58.0, then angle 2 = ()


Question: As shown in the figure, put the right-angled vertex of a right triangle board on one side of the ruler, if angle 1 = 30.0, then angle 2 is ()


Question: As shown in the figure, AB perpendicular  CD at D, DE perpendicular  DF, if angle BDE = 60.0, then angle CDF is equal to ()


Question: As shown in the figure, the measured BD = 120.0, DC = 60.0, EC = 50.0, then the width of the river AB is ()


Question: As shown in the figure, in triangle ABE, the perpendicular bisector of AE MN intersects BE at point C, angle E = 30.0, and AB = CE, then the degree of angle BAE is ()


Question: As shown in the figure, in triangle ABC, D and E are points on edges AB and AC respectively, DE parallel  BC, angle ADE = 35.0, angle C = 120.0, then angle A is ()


Question: As shown in the figure, points A, B, and C are on circle O, angle AOB = 72.0, then angle ACB is equal to ()


Question: Fold a rectangular piece of paper as shown in the picture, and then unfold it. If angle 1 = 56.0, then angle 2 is equal to ()


Question: As shown in the figure, the straight line a parallel  b, angle 1 = 72.0, then the degree of angle 2 is ()


Question: As shown in the figure, the two vertices of a right triangle with 30.0 angle are placed on the opposite side of a rectangle. If angle 1 = 25.0, then the degree of angle 2 is ()


Question: As shown in the figure, it is known that AB and AD are the chords of circle O, angle ABO = 30.0, angle ADO = 20.0, then angle BAD = ()


Question: As shown in the figure, C and D are two points on the line segment AB, if CB = 4.0, DB = 7.0, and D is the midpoint of AC, then the length of AB is equal to ()


Question: As shown in the figure, C and D are two points on the line segment AB, if AC = 3.0, C is the midpoint of AD and AB = 10.0, then DB = ()


Question: As shown in the figure, in circle O, AC is the diameter, MA and MB are tangent to circle O at points A, B, angle BAC = 25.0, then the size of angle AMB is ()


Question: Given: AB parallel  CD, angle ABE = 120.0, angle C = 25.0, then the degree of angle α is ()


Question: As shown in the figure, the straight lines AB and CD intersect at point O, OD bisects angle AOE, angle BOC = 50.0, then angle EOB = ()


Question: As shown in the figure, a big tree breaks at B whose height is 9.0 from the ground, and the top A of the tree falls at 12.0 from the bottom C of the tree. The height before the break is ()


Question: As shown in the figure, cross point A on circle O to draw a tangent of circle O, and it intersects the extended line of diameter BC at point D, connect AB, if angle B = 25.0, then the degree of angle D is ()


Question: As shown in the figure, place the right-angled vertex of the triangular plate (angle A = 30.0) with 30.0 angle on one of the two parallel lines. If angle 1 = 38.0, then the degree of angle 2 ()


Question: As shown in the figure, Xiaoming walks from point A in the direction of 80.0 to the north by east to point B, and then from point B to the direction of 25.0 to the south by west to point C, then the degree of angle ABC is ()


Question: As shown in the figure, given that the straight lines AB and CD intersect at point O, OE perpendicular  AB, angle EOC = 30.0, then the degree of angle BOD is ()


Question: The three views of a geometry are shown in the figure, where the front view and the left view are both equilateral triangles with edge length 2.0, then the surface area of the geometry is ()


Question: As shown in the figure, in the right triangle ABC, angle C = 90.0, AB = 5.0, AC = 4.0, then the value of sinangle B is ()


Question: As shown in the figure, in Rttriangle ABC, angle C is a right angle, CD perpendicular  AB at D, it is known that AC = 3.0, AB = 5.0, then tanangle BCD is equal to ()


Question: As shown in the figure, in triangle ABC, DE parallel  BC, if AD = 3.0, DB = 6.0, DE = 2.5, then the length of BC is ()


Question: As shown in the figure, in Rttriangle ABC, angle BAC = 90.0, AB = 3.0, AC = 4.0, point P is any point on BC, connect PA, take PA and PC as adjacent edges to make parallelogram PAQC, connect PQ, then the minimum value of PQ is ()


Question: As shown in the figure, AB parallel  CD, AB = 6.0, CD = 9.0, AD = 10.0, then the length of OD is ()


Question: As shown in the figure, in triangle ABC, DE parallel  BC, intersect AB and AC at points D and E respectively. If AD = 2.0, DB = 3.0, BC = 6.0, then the length of DE is ()


Question: As shown in the figure, AB is the diameter of circle O, C is the point on circle O, chord AD bisects angle BAC, intersects BC at point E, AB = 6.0, AD = 5.0, then the length of DE is ()


Question: As shown in the figure, in triangle ABC, DE parallel  BC, frac {AD}{DB}=frac {1.0}{2.0},DE=4.0, then the length of BC is ()


Question: As shown in the figure, AD•AB = AE•AC, angle ADE = 80.0, angle A = 60.0, then angle B = ()


Question: As shown in the figure, DC parallel  EF parallel  AB, iffrac {EG}{AB}=frac {1.0}{2.0},DC=6.0, then the length of GF is ()


Question: As shown on the right, in triangle ABC, DE parallel  BC, frac {AD}{AB}=frac {2.0}{5.0},DE=3.0,then the length of BC is ()


Question: As shown in the figure, in the parallelogram ABCD, E is the midpoint of BC, and AE and BD intersect at point F. If the area of triangle BFE is 3.0, then the area of triangle ABF is ()


Question: As shown in the figure, in triangle ABC, D and E are the midpoints of AB and AC respectively. It is known that the area of triangle ADE is 1.0, then the area of triangle ABC is ()


Question: As shown in the figure, it is known that AB, CD, and EF are parallel to each other, and AB = 1.0, CD = 4.0, then the length of EF is ()


Question: As shown in the figure, in triangle ABC, DE parallel  BC, intersect AB and AC at points D and E respectively. If AE = 3.0, EC = 6.0, then the value of frac  DEBC is ()


Question: As shown in the figure, BE and CF are the two heights of triangle ABC. If AB = 6.0, BC = 5.0, EF = 3.0, then the length of AE is ()


Question: As shown in the figure, the inclination angle angle ABD of the stairs AB with the length 4.0 is 60.0. In order to improve the safety performance of the stairs, the stairs are prepared to be rebuilt so that the inclination angle angle ACD is 45.0, then the length of the adjusted stairs AC is ()


Question: As shown in the figure, the cross section of the dam, the horizontal width of the slope AB is 12.0, and the slope of the slope is 1.0:2.0, then the length of the slope AB is ()


Question: As shown in the figure, the cable is fixed at the height of 5.0 from the ground to fix the pole, the cable and the ground form an angle 60.0, then the length of the cable AC is ()


Question: As shown in the figure, in triangle ABC, points D and E are the midpoints of AB and AC respectively. If the area of triangle ADE is 4.0, then the area of triangle ABC is ()


Question: As shown in the figure, in the rectangle ABCD, AB = 4.0, BC = 2.0, point M is on BC, connect AM to make angle AMN = angle AMB, point N is on the straight line AD, MN intersects CD at point E, then the maximum value of BM•AN is ()


Question: As shown in the figure, in triangle ABC, angle ACB = 90.0, CD perpendicular  AB at D, CD = 4.0, BC = 5.0, then AC = ()


Question: As shown in the figure, there is a square DEFG in triangle ABC, where D is on AC, E and F are on AB, and the straight line AG intersects DE and BC at M and N points respectively. If angle B = 90.0, AB = 8.0, BC = 6.0, EF = 2.0, then the length of BN is ()


Question: As shown in the figure, in triangle ABC, points D and E are points on edges AB and AC respectively, and DE parallel  BC, if AD = 5.0, BD = 10.0, DE = 3.0, then the length of BC is ()


Question: As shown in the figure, triangle ABC is inscribed in circle O, angle BAC = 120.0, AB = AC, BD is the diameter of circle O, AB = 3.0, then the value of AD is ()


Question: As shown in the figure, in circle O, angle ABC = 130.0, then angle AOC is equal to ()


Question: As shown in the figure, AC and BC are the diameters of two semicircles, angle ACP = 30.0, if AB = 20.0, the value of PQ is ()


Question: As shown in the figure, in the quadrilateral ABCD, AB = AC = AD, angle CBD = 23.0, then angle CAD is ()


Question: As shown in the figure, circle O is the circumscribed circle of triangle ABC, angle BCO = 40.0, then the degree of angle A is equal to ()


Question: As shown in the figure, A, B, and C are three points on circle O, angle ABC = 25.0, then the degree of angle AOC is ()


Question: As shown in the figure, A, B, and C are points on circle O, angle ACB = 32.0, then angle AOB is equal to ()


Question: As shown in the figure, points A, B, and C are on circle O, if angle ABC = 35.0, then the degree of angle AOC is ()


Question: As shown in the figure, points A, B, and C are on circle O and connect AB and AC. If angle BOC = 100.0, then the degree of angle B + angle C is ()


Question: As shown in the figure, place the vertex of the right triangle 45.0 angle on the center O, the hypotenuse and the leg intersect circle O at two points A and B respectively, and C is any point on the major arc AB (not coincident with A and B) , Then the degree of angle ACB is ()


Question: As shown in the figure, the line segment AB is the diameter of circle O, the chord CD 丄 AB, angle CAB = 20.0, then angle AOD is equal to ()


Question: As shown in the figure, the vertices A, B, and D of parallelogram ABCD are on circle O, and the vertex C is on the diameter BE of circle O, connect AE, angle E = 36.0, then the degree of angle ADC is ()


Question: The diameter of the protractor coincides with the hypotenuse AB of the right triangle ABC, where the endpoint N of the scale line of the protractor O coincides with point A, the radial CP starts from CA and rotates clockwise at a speed of 3.0 degrees per second, and CP and the semicircular arc of the protractor intersect at point E, when the 20.0 second, the corresponding reading of point E on the protractor is ()


Question: As shown in the figure, the three points A, B, and C are on circle O, and angle ABO = 50.0, then angle ACB is equal to ()


Question: AB is the diameter of circle O, point C is on circle O, if angle C = 15.0, then angle BOC = ()


Question: As shown in the figure, the two chords AB and CD in the circle intersect at E, angle D = 35.0, angle AEC = 105.0, then angle C = ()


Question: As shown in the figure, AB and CD are the two chords of circle O, connect AD and BC. If angle BCD = 70.0, then the degree of angle BAD is ()


Question: As shown in the figure, A, B, and C are on circle O, if angle BAC = 24.0, then the degree of angle BOC is ()


Question: As shown in the figure, points A, B, and C are all on circle O, if angle C = 34.0, then angle AOB is ()


Question: As shown in the figure, circle A with a diameter of 10.0 passes through point C(0.0,5.0) O(0.0,0.0), B is a point on the circle A major arc on the right side of the y-axis, then the degree of angle OBC is ()


Question: As shown in the figure, triangle ABC is inscribed in circle O, angle A = 15.0, connect OB, then angle OBC is equal to ()


Question: As shown in the figure, in circle O, angle ABC = 40.0, then angle AOC = () degrees.


Question: As shown in the figure, A, B, C are the three points on circle O, and angle CAO = 25.0, angle BCO = 35.0, then the degree of angle AOB is ()


Question: As shown in the figure, AB is the diameter of circle O, chord CD perpendicular  AB, E is a point of arc BC, if angle CEA = 28.0, then the degree of angle ABD is ()


Question: As shown in the figure, circle O is the circumscribed circle of triangle ABC, and it is known that angle B = 70.0, then the degree of angle CAO is ()


Question: As shown in the figure, circle O is the circumscribed circle of triangle ABC, angle OCB = 30.0, then the degree of angle A is equal to ()


Question: As shown in the figure, circle O is the circumscribed circle of triangle ABC, AB is the diameter, if angle BOC = 70.0, then angle A is equal to ()


Question: As shown in the figure, in circle O, diameter AB = 5.0, chord AC = 4.0, then the distance from point O to line AC is ()


Question: As shown in the figure, AB is the diameter of circle O, if angle BAC = 35.0, then angle ADC = ()


Question: A pair of right triangle plates are placed as shown (angle ACB = angle ADB = 90.0 ), angle CAB = 30.0, angle BAD = 45.0, AB intersects CD at E, then the degree of angle CEB is ()


Question: As shown in the figure below, point C is on the semicircle O with AB as the diameter, angle BAC = 20.0, then angle BOC is equal to ()


Question: As shown in the figure, AB is the diameter of circle O, angle ABC = 25.0, then the degree of angle D is ()


Question: As shown in the figure, triangle ABC is the inscribed triangle of circle O, BD is the diameter, if angle DBC = 18.0, then the degree of angle A is ()


Question: As shown in the figure, AB and CD are the chords of circle O, and AB parallel  CD, if angle BAD = 36.0, then angle AOC is equal to ()


Question: As shown in the figure, A, B, and C are the three points on circle O, if angle C = 35.0, then the degree of angle OAB is ()


Question: As shown in the figure, the vertices A, B, and D of parallelogram ABCD are on circle O, and the vertex C is on the diameter BE of circle O, angle ADC = 54.0, connect AE, then the degree of angle AEB is ()


Question: As shown in the figure, CD is the diameter of circle O, chord DE parallel  OA, if the degree of angle D is 50.0, then the degree of angle A is ()


Question: As shown in the figure, it is known that circle O is the circumscribed circle of triangle ABC, angle AOB = 110.0, then the degree of angle C is ()


Question: As shown in the figure, AB is the diameter of circle O, and point C is on circle O. If angle A = 40.0, then the degree of angle B is ()


Question: As shown in the figure, if AB is the diameter of circle O, CD is the chord of circle O, angle ABD = 55.0, then the degree of angle BCD is ()


Question: As shown in the figure, points A, B, and C are three points on circle O, angle BAC = 40.0, then the degree of angle BOC is ()


Question: As shown in the figure, in the circle O with a radius of 5.0, if the length of the chord AB is 8.0, then its distance from the chord OC to the centre is equal to ()


Question: As shown in the figure, point O is the center of circle O, points A, B, and C are on circle O, AO parallel  BC, angle AOB = 40.0, then the degree of angle OAC is equal to ()


Question: It is known that: as shown in the figure, the diameter AB of circle O is perpendicular to the chord CD, and the foot of perpendicular is E. If AB = 10.0, CD = 6.0, then the length of BE is ()


Question: As shown in the figure, the radius of circle O is 10.0, AB is the chord, OC perpendicular  AB, and the foot of perpendicular is E. If CE = 4.0, then the length of AB is ()


Question: As shown in the figure, the edge length of the square ABCD is 3.0, and the equilateral triangle PCD and equilateral triangle QCD are made on both sides of CD with CD as one edge, then the length of PQ is ()


Question: As shown in the figure, in the square ABCD, E is a point on DC, F is a point on the extended line of BC, angle BEC = 70.0, and triangle BCE congruent  triangle DCF. Connect EF, then the degree of angle EFD is ()


Question: As shown in the figure, it is known that the radius of circle O is 5.0 and the chord AB = 8.0, then the distance from the center O to AB is ()


Question: As shown in the figure, MN is tangent to circle O at point A, angle AOB = 60.0, then angle BAM is equal to ()


Question: As shown in the figure, the tangents PA and PB of a circle drawn from a point P outside circle O, the tangent points are A and B respectively, if angle APB = 70.0, then the degree of the minor arc AB sandwiched by these two tangents is ()


Question: As shown in the figure, PB is tangent to circle O at point B, PO intersects circle O at point E, extends PO and intersects circle O at point A, connects AB, the radius of circle O OD perpendicular  AB at point C, BP = 6.0, angle P = 30.0 , then the length of CD is ()


Question: As shown in the figure, PA and PB are tangent to circle O to A and B respectively. Point C and point D are the moving points on line segments PA and PB, and CD always remains tangent to circle O. If PA = 8.0, then perimeter of triangle PCD is ()


Question: As shown in the figure, in the two concentric circles, the chord AB of the great circle is tangent to the small circle at point C. If AB = 6.0, the area of the ring is ()


Question: As shown in the figure, the squares P and Q are sandwiched in the ABCD frame, the angle between the lower edge of the square P and AB is 15.0, and the angle between the two adjacent edges of the square P and Q is 150.0, then angle 1 is ()