奈格尔点与外切三角形

GeoGebra 命令及参数

1. Line(A, B) → a
2. Line(B, C) → b
3. Line(C, A) → c
4. AngularBisector(B, A, C) → d
5. AngularBisector(C, B, A) → e
6. AngularBisector(A, C, B) → f
7. Intersect(d, e) → I
8. OrthogonalLine(I, c) → g
9. Intersect(c, g) → D
10. Circle(I, D) → h
11. Circle(B, A, C) → p
12. Center(p) → O
13. OrthogonalLine(A, d) → i
14. OrthogonalLine(B, e) → j
15. Intersect(f, i) → E
16. Intersect(e, i) → F
17. Intersect(d, j) → G
18. OrthogonalLine(E, c) → k
19. Intersect(c, k) → H
20. Circle(E, H) → q
21. OrthogonalLine(F, b) → m
22. Intersect(b, m) → J
23. Circle(F, J) → r
24. OrthogonalLine(G, a) → n
25. Intersect(a, n) → K
26. Circle(G, K) → s
27. Intersect(r, c, 1) → B'
28. Intersect(q, a, 1) → C'
29. Intersect(s, b, 1) → A'
30. Polygon(A', C', B') → poly1, l_1, n_1, m_1
31. Segment(B, B') → t
32. Segment(A, A') → a_1
33. Segment(C', C) → b_1
34. Intersect(t, a_1) → N_a
35. Mirror(N_a, c) → N_{a1}
36. Mirror(N_a, b) → N_{a2}
37. Mirror(N_a, a) → N_{a3}
38. Circle(N_{a3}, N_{a1}, N_{a2}) → c_1
39. Center(c_1) → N'_a
40. Dilate(p, l, N'_a) → p'