三角形九点圆的尺规作图演示

GeoGebra 命令及参数

1. Polygon(A, B, C) → d1, c, a, b
2. Line(A, B) → f
3. Line(B, C) → g
4. Line(C, A) → h
5. OrthogonalLine(A, g) → i
6. OrthogonalLine(B, h) → j
7. OrthogonalLine(C, f) → k
8. Intersect(i, j) → H
9. Intersect(k, f) → H_c
10. Intersect(i, g) → H_a
11. Intersect(j, h) → H_b
12. Angle(B, H_c, H) → α
13. Angle(A, H_b, H) → β
14. Angle(C, H_a, H) → γ
15. Segment(H, H_a) → l
16. Segment(H, H_c) → m
17. Segment(H, H_b) → n
18. Segment(H, B) → p
19. Segment(H, C) → q
20. Segment(H, A) → r
21. Circle(A, B, C) → d
22. Center(d) → U
23. OrthogonalLine(U, f) → s
24. OrthogonalLine(U, g) → t
25. OrthogonalLine(U, h) → e
26. Intersect(e, h) → M_b
27. Intersect(s, f) → M_c
28. Intersect(t, g) → M_a
29. Segment(U, M_c) → f_1
30. Segment(U, M_a) → g_1
31. Segment(U, M_b) → h_1
32. Circle(M_c, H) → c_1
33. Circle(M_a, H) → d_1
34. Circle(M_b, H) → e_1
35. Intersect(e_1, h) → T, S_{1}
36. Intersect(d_1, g) → P, O
37. Intersect(c_1, f) → R, Q
38. Circle(S_{1}, R, Q) → k_1
39. Segment(M_a, M_b) → i_1
40. Segment(M_c, M_b) → j_1
41. Segment(M_c, M_a) → l_1
42. Circle(H_a, M_a, H_c) → p_1
43. Center(p_1) → N
44. Segment(N, U) → m_1
45. Segment(N, H) → n_1
46. Polygon(H_c, H_a, H_b) → d2, h_b, h_c, h_a
47. Intersect(d_1, e_1, 2) → D
48. Intersect(c_1, d_1, 2) → E
49. Intersect(c_1, e_1, 2) → F
50. Segment(A, M_a) → q_1
51. Segment(M_b, B) → r_1
52. Segment(C, M_c) → s_1
53. Intersect(q_1, r_1) → S