用作垂线交点定位垂心：画出XYZ并关联围心

GeoGebra 命令及参数

1. Polygon(A, B, C) → d1, c, a, b
2. OrthogonalLine(A, a) → f
3. OrthogonalLine(B, b) → g
4. OrthogonalLine(C, c) → h
5. Intersect(f, g) → H
6. Intersect(f, a) → H_a
7. Intersect(g, b) → H_b
8. Intersect(h, c) → H_c
9. Segment(A, H_a) → i
10. Segment(B, H_b) → j
11. Segment(C, H_c) → k
12. Circle(H_a, H) → d
13. Circle(H_c, H) → e
14. Circle(H_b, H) → p
15. Intersect(d, h, 2) → G
16. Intersect(d, g, 2) → I
17. Intersect(p, h, 2) → J
18. Intersect(p, f, 2) → K
19. Intersect(e, g, 2) → L
20. Intersect(e, f, 2) → M
21. Line(I, G) → l
22. Line(K, J) → m
23. Line(L, M) → n
24. Intersect(l, m) → Z
25. Intersect(m, n) → X
26. Intersect(l, n) → Y
27. Polygon(X, Y, Z) → d2, z_1, x_1, y_1
28. OrthogonalLine(X, l) → t
29. OrthogonalLine(Y, m) → f_1
30. OrthogonalLine(Z, n) → g_1
31. Intersect(t, f_1) → U
32. Intersect(l, t) → N
33. Segment(X, N) → h_1
34. Intersect(m, f_1) → O
35. Segment(Y, O) → i_1
36. Intersect(n, g_1) → P
37. Segment(Z, P) → j_1
38. Circle(U, A) → c_1
39. Intersect(c_1, f) → D, E
40. Intersect(c_1, g) → F, Q
41. Intersect(c_1, h) → R, S
42. Polygon(R, E, F) → d3, f_2, r, e_1