无字证明：三角形面积

GeoGebra 命令及参数

1. Segment(C, A) → d
2. Line(A, xAxis) → a
3. Point(Ray[A, A + (1, 0)]) → B
4. AngularBisector(C, B, A) → f
5. AngularBisector(B, A, C) → e
6. Intersect(e, f) → I
7. OrthogonalLine(I, d) → h
8. Intersect(h, d) → F
9. OrthogonalLine(I, a) → g
10. Intersect(g, a) → D
11. Translate(P, Vector[A, D]) → G'
12. Translate(G', Vector[D, B]) → G''
13. Segment(B, C) → c
14. OrthogonalLine(I, c) → i
15. Intersect(i, c) → E
16. Segment(A, B) → b
17. Circle(I, D) → k
18. Segment(I, A) → j
19. Segment(I, B) → l
20. Segment(I, C) → m
21. Segment(I, D) → n
22. Segment(I, E) → p
23. Segment(I, F) → q
24. Translate(G', Vector[D, I]) → G''_1
25. Translate(G'', Vector[D, I]) → G'''
26. Translate(Rotate[F, (-(180° + Angle[B, A, C])), C], Vector[C, G'']) → R
27. Translate(R, Vector[D, I]) → H'
28. Translate(P, Vector[D, I]) → Q
29. Segment(P, Q) → r
30. Segment(P, R) → t_1
31. Angle(I, D, A) → α
32. Angle(I, E, B) → β
33. Angle(I, F, C) → γ
34. Polygon(P, R, H', Q) → poly1, p_1, r_1, h', q_1
35. Segment(A, D) → s
36. Segment(B, E) → a_1
37. Segment(C, F) → b_1
38. Midpoint(q_1) → G
39. Polygon(C, A, B) → poly2, b_2, c_1, a_2
40. Midpoint(h') → H
41. Midpoint(t_1) → J