In △ ABC, ab = AC, D is the midpoint of BC, e and F are on AB and AC respectively, and △ DEF is an equilateral triangle

It is proved that DME is equal to dnf by making high DM and DN on AB AC through D point

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1. As shown in the figure, △ ABC is a right triangle, ∠ ACB = 90, ad is the bisector of ∠ BAC, de ⊥ AB, BC = 8, CD = 3, the length of 1.be, 2. The area of △ ABC
2. It is known that: as shown in the figure, in △ ABC, the bisector am of ∠ C = 90 °, BAC = 60 ° is 15cm, and the length of BC is calculated
3. As shown in the figure, it is known that △ ABC is an isosceles right triangle, ∠ BAC = 90 °, be is the bisector of ∠ ABC, de ⊥ BC, and the perpendicular foot is d. (1) please write all isosceles triangles in the figure; (2) please judge whether AD is perpendicular to be? (3) if BC = 10, find the length of AB + AE
4. ABC is isosceles right triangle, ∠ BAC = 90 °, be is angle horizontal line, ed ⊥ BC, prove ad vertical be
5. It is known that: as shown in the figure, in △ ABC, the bisector am of ∠ C = 90 °, BAC = 60 ° is 15cm, and the length of BC is calculated
6. As shown in the figure, in the triangle ABC, AC equals BC and the angle ACB equals 90 degrees Let AE be equal to half BD, and prove that BD is the bisector of angle ACB
7. As shown in the figure, in the triangle ABC, the angle ACB is equal to 90 degrees, the points D and E are the midpoint of AC and ab respectively, the point F is on the extension line of BC, and the angle CDF is equal to the angle A. It is proved that the quadrilateral decf is a parallelogram
8. Given that D and E are two points on the edge BC of △ ABC, and ∠ bad = ∠ C, ∠ DAE = ∠ EAC, it is proved that BD ratio AB is equal to de ratio CE
9. As shown in the figure, in △ ABC, D and E are on the straight line BC. (1) if AB = BC = AC = CE = BD, calculate the degree of ∠ EAC; (2) if AB = AC = CE = BD, ∠ DAE = 100 °, calculate the degree of ∠ EAC
10. As shown in the figure, in △ ABC, ab = AC, D, e are two points on the straight line BC, and ab & # 178; = DB × CE, if ∠ BAC = 40 °, calculate the degree of ∠ DAE
11. In a right triangle ABC, angle a is a right angle, point D is the midpoint of BC, e is on AB, f is on AC, De is perpendicular to DF, and we prove that EF square = be square + CF square
12. Ad is the bisector of triangle ABC, De is parallel to AC, de intersects AB with E, DF is parallel to AB, DF intersects AC with F. what is the relationship between angle EDA and angle ADF?
13. Ad is the height of triangle ABC, de ⊥ AB, DF ⊥ AC, and the vertical foot is a and e respectively. Try to judge the size of ∠ ADF and ∠ AEF and explain the reason Using similar triangle to solve the problem
14. If the right angle vertex C of RT △ ABC is in plane a, the hypotenuse ab ‖ a, and the distance between AB and a is root 6, the projective points of a and B in a are A1 and B1 respectively, and A1C = 3, B1C = 4, then ∠ a1cb1=
15. As shown in the figure, in the isosceles right angle △ ABC, ∠ ABC = 90 °, point D is on AC, and △ CBE is obtained after △ abd is rotated 90 ° clockwise around vertex B. (1) calculate the degree of ∠ DCE; (2) when AB = 4, ad: DC = 1:3, calculate the length of de
16. Given a + B + C = 0, ABC = - 15, find AA (B + C) + BB (a + C) + CC (a + b)
17. Ask math question AA + BB + CC = ABC What are the ABC numbers?
18. As shown in the figure, △ ABC rotates counterclockwise to the position of △ ab ′ C ′ so that AC bisects BB ′
19. It is known that △ ABC is all equal to △ def, the perimeter of △ ABC is 32, ab = 8, BC = 12, then CA =?, de =? EF =?
20. If the triangle ABC is equal to the triangle def, the circumference of the triangle ABC is 70cm, De is 30cm, DF is 25cm, and the angle B is 25cm