圆外角定理

GeoGebra 命令及参数

1. Circle(A, B) → c
2. Circle(C, D) → d
3. Circle(E, F) → e
4. Tangent(G, c) → a, b
5. Intersect(c, a, 1) → H
6. Intersect(c, b, 1) → I
7. Segment(G, H) → f
8. Segment(G, I) → g
9. Tangent(J, d) → h, i
10. Intersect(d, h, 1) → K
11. Segment(J, K) → j
12. Point(d) → L
13. Segment(J, L) → k
14. Point(e) → N
15. Segment(M, N) → l
16. Point(e) → O
17. Segment(M, O) → m
18. Angle(H, G, I) → α
19. Angle(K, J, L) → β
20. Angle(N, M, O) → γ
21. Intersect(d, k, 2) → P
22. Intersect(e, l, 2) → Q
23. Intersect(e, m, 2) → R
24. Angle(P, C, K) → δ
25. Angle(K, C, L) → ε
26. Angle(H, A, I) → ζ
27. Point(c) → S
28. Angle(I, A, H) → η
29. Angle(R, E, Q) → θ
30. Angle(N, E, O) → ι