三个相似三角形与切线构造

GeoGebra 命令及参数

1. Point(xAxis) → A
2. Point(xAxis) → B
3. Semicircle(A, B) → c
4. Point(c) → C
5. Polygon(C, A, B) → poly1, b, c_1, a
6. Polygon(C, D, B) → poly2, b_1, c_2, d
7. Polygon(C, D, A) → poly3, a_1, c_3, d_1
8. Circle(E, Distance[A, D]) → e
9. Point(e) → F
10. Segment(E, F) → f
11. OrthogonalLine(F, f) → g
12. Circle(E, Distance[A, C]) → h
13. Intersect(h, g) → G, H
14. Segment(E, H) → i
15. Segment(F, H) → j
16. Circle(I, Distance[B, D]) → k
17. Point(k) → J
18. Segment(I, J) → l
19. OrthogonalLine(J, l) → m
20. Circle(I, Distance[B, C]) → p
21. Intersect(p, m) → K, L
22. Segment(K, I) → n
23. Segment(J, K) → q
24. Angle(E, H, F) → α
25. Angle(A, C, D) → β
26. Angle(J, K, I) → γ
27. Angle(D, C, B) → δ
28. Angle(C, D, A) → ε
29. Angle(B, D, C) → ζ
30. Angle(H, F, E) → η
31. Angle(I, J, K) → θ
32. Segment(C, D) → r
33. Polygon(E, F, H) → poly3copy, h_1, e_1, f_1
34. Polygon(J, I, K) → poly2copy, k_1, j_1, i_1
35. Distance(E, K) → EK
36. Distance(B, C) → BC
37. Distance(I, K) → IK
38. Distance(A, B) → AB
39. Angle(F, E, H) → ι
40. Angle(D, A, C) → κ
41. Angle(K, I, J) → λ
42. Angle(C, B, D) → μ