In the triangle ABC, ab = AC, points D, e and F are on the sides of AB, BC and AC respectively. De = DF and EDF = angle a are known. Find out the similar triangles in the graph and prove them

① The proof of ∫ ABC ∫ def: ∫ AB = AC, de = DF ∫ AB / de = AC / DF and ∫ a = ∠ EDF ∫ ABC ∫ def (SAS) ② ∫ DBE ∫ ECF: the proof of ∫ ABC ∫ def ∫ def = ∠ B ∫ CEF + ∠ bed = 180 ° - def} BDE + ∠ bed = 180 ° - B ∫ CEF = ∠ BDE ∫ AB = AC ∫ B =

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1. It is known that: as shown in the figure, in △ ABC, ∠ B = ∠ C, points D, e and F are points on edges BC, AB and AC respectively, be = CD, connecting de and DF, with ∠ EDF = ∠ C, then are de and DF equal? Try to explain the reason
2. It is known that: as shown in the figure, in △ ABC, ∠ B = ∠ C, points D, e and F are points on edges BC, AB and AC respectively, be = CD, connecting de and DF, with ∠ EDF = ∠ C, then are de and DF equal? Try to explain the reason
3. As shown in the figure, △ ABC, D is the midpoint of BC, e and F are two points on the edge of AB and AC respectively, ed ⊥ FD, which proves that be + CF > EF
4. As shown in the figure, in △ ABC, BD bisects ∠ ABC, de ‖ BC intersects AB at point E, EF ‖ AC intersects BC at point F. try to guess the size relationship between be and CF, and explain the reasons, as shown in figure.doc
5. In △ ABC, ab = AC, D is a point on BC, de ⊥ AB and E, DF ⊥ BC, intersection AC and F, ∠ AFD = 160 °, find the degree of ∠ A and ∠ EDF RT
6. It is known that in the triangle ABC, the angle a is equal to 50 ° and DEF is the point on BC AB AC, DB= de.dc=df , find the angle EDF
7. In the triangle ABC, ab = AC, point D is on AC, and BD = BC = ad, De is the middle line of the triangle abd, and DF = BF, find the degree of ∠ EDF
8. As shown in the figure, in △ ABC, ab = AC, EB = BD = DC = CF, ∠ a = 40 °, then the degree of ∠ EDF is______ Degree
9. As shown in the figure: in △ ABC, D is the point on BC, de ⊥ Ba is in E, DF ⊥ AC is in F, and de = DF? And explain the reason
10. As shown in the figure: in △ ABC, D is the point on BC, de ⊥ Ba is in E, DF ⊥ AC is in F, and de = DF? And explain the reason
11. In △ ABC, ab = AC, points D, e and F are on the sides of AB, BC and AC respectively, de = DF,
12. As shown in the figure, ab = De, AC ∥ DF, BC ∥ EF
13. In RT △ ABC, ∠ C = 90 °, a right triangle is solved by the following conditions (1) If we know that a = 4 times radical 3, B = 2 times radical 3, then C =? (2) If a = 10, C = 10 times the root 2, then ∠ B =? (3) If C = 20 and a = 60 ° are known, then a =? (4) If B = 35 and a = 45 ° are known, then a =?
14. In RT △ ABC, a = 30.01, ∠ B = 80 ° 24 'and ∠ C = 90 °, right triangle can be solved according to the following conditions
15. The side length of equilateral △ ABC is a, and the area of inscribed square defg of its inscribed circle is obtained
16. The square defg is the inscribed square of △ ABC, D is on ab. G is on AC, e and F are on BC, am ⊥ BC is on M, intersecting DG is on H. if ah is 4 and the side length of the square is 6, the length of BC is calculated
17. As shown in the figure, the area of triangle ABC is 120 square centimeters, D is the midpoint of BC & nbsp;, AE = 13be, EF = 12fd, then the area of triangle AFD is______ Square centimeter
18. Draw a rectangular piece of land on the plan with a scale of 1:200. The circumference of the rectangle on the plan is 54 cm, Draw a rectangular piece of land on the plan with a scale of 1:200. The perimeter of the rectangle is 54 cm and the ratio of length to width is 5:4. Calculate the actual area of the rectangular land
19. Xiaoming's father drew a 1:200 scale plan for a site and asked Xiaoming, "do you know how many times the actual area of the site is the size of the plan
20. Move the square with an area of 64 square centimeters on the plan with a scale of 1:250 to the plan with a scale of 100 square centimeters?