圆内接角定理：你看到了什么？

GeoGebra 命令及参数

1. Circle(A, B) → c
2. Segment(B, A) → a
3. Point(c) → C
4. Segment(A, C) → b
5. Point(c) → D
6. CircumcircleArc(C, D, B) → d
7. CircleArc(A, B, C) → e
8. Point(d) → E
9. Segment(C, E) → f
10. Segment(E, B) → g
11. Circle(E, 1.5) → h
12. Ray(E, C) → i
13. Ray(E, B) → j
14. Intersect(h, j) → F,
15. Intersect(h, i) → G,
16. CircleSector(E, F, G) → k
17. Segment(E, A) → l
18. Line(A, xAxis) → m
19. Dilate(E, If[0 ≤ n ≤ 1, 1 - n, 0], A) → E'
20. Vector(E, E') → u
21. Translate(k, u) → k'
22. Line(E, a) → p
23. Line(E, b) → q
24. Intersect(h, p, 1) → H
25. Angle(H, E, B) → α
26. Intersect(h, q, 2) → I
27. Angle(C, E, I) → β
28. Dilate(E, If[1 < n ≤ 2, 2 - n, 0], A) → E'_1
29. Vector(E, E'_1) → v
30. Translate(k, v) → k'_1
31. Rotate(k'_1, If[1 < n ≤ 2, ((n - 1) * β), β], E'_1) → k''
32. Rotate(k', If[0 < n ≤ 1, ((-n) * α), (-α)], E') → k''_1
33. Circle(A, 1.5) → r
34. Intersect(r, a, 1) → J
35. Intersect(r, b, 1) → K
36. CircleSector(A, J, K) → s