平行线与角的关系问题解决方案

GeoGebra 命令及参数

1. Rotate(B, α, A) → B'
2. Angle(B, A, B') → β
3. Line(A, B') → f
4. Line(C, f) → g
5. OrthogonalLine(C, f) → h
6. Intersect(f, h) → D
7. PointIn(d) → E
8. Segment(C, E) → i
9. Segment(E, D) → j
10. Min(i, j) → k
11. Circle(C, (0.25 * k)) → p
12. Circle(D, (0.25 * k)) → q
13. Intersect(q, f) → F, G
14. Intersect(q, j) → H,
15. Intersect(p, g) → I, J
16. Intersect(p, i) → K,
17. CircleSector(C, I, K) → r
18. CircleSector(D, H, F) → s
19. Dilate(C, If[0 < m ≤ 1, 1 - m, 0], E) → C'
20. Vector(C, C') → u
21. Translate(r, u) → r'
22. Rotate(r', If[1 < m ≤ 2, ((m - 1) * π), π], E) → r''
23. Dilate(D, If[2 < m ≤ 3, 3 - m, 0], E) → D'
24. Vector(D, D') → v
25. Translate(s, v) → s'
26. Rotate(s', If[3 < m ≤ 4, ((m - 3) * π), π], E) → s''
27. Circle(E, (0.25 * k)) → t
28. Intersect(t, j) → M,
29. Intersect(t, i) → N,
30. CircleArc(E, M, N) → c_1