内错角定理

GeoGebra 命令及参数

1. Point(a) → B
2. Rotate(B, α, A) → B'
3. Angle(B, A, B') → β
4. Line(A, B') → b
5. Circle(A, 1) → e
6. Intersect(b, d) → C
7. Circle(C, 1) → f
8. Intersect(e, a) → D, E
9. Intersect(e, b) → F, G
10. Intersect(f, b) → H, I
11. Intersect(f, d) → J, K
12. CircleSector(C, J, H) → k
13. CircleSector(C, H, K) → p
14. CircleSector(A, E, G) → q
15. CircleSector(A, G, D) → r
16. CircleSector(A, F, E) → t
17. Dilate(A, If[0 < i < 1, 1 - i], C) → A'
18. Vector(A, A') → u
19. Translate(q, u) → q'
20. Translate(r, u) → r'
21. Translate(t, u) → t'
22. CircleArc(A, E, G) → c_1
23. CircleArc(A, G, D) → f_1
24. CircleArc(C, J, H) → h_1
25. CircleArc(C, H, K) → p_1
26. Vector(A, C) → v
27. Translate(q, v) → q'_1
28. Rotate(q'_1, (((-(i - 1)) * 180))°, C) → g
29. Translate(r, v) → r'_1
30. Rotate(r'_1, (((i - 1) * 180))°, C) → h