利用梯形对角线交点作垂线平分角

GeoGebra 命令及参数

1. Polygon(A, B, C) → poly1, c, a, b
2. Circle(A, B, C) → d
3. AngularBisector(b, c) → e, f
4. AngularBisector(a, b) → g, h
5. AngularBisector(a, c) → i, j
6. Intersect(f, h) → O
7. OrthogonalLine(O, b) → k
8. Intersect(k, b) → E
9. Segment(O, E) → r
10. Circle(O, r) → p
11. LineBisector(a) → l
12. LineBisector(c) → m
13. Intersect(l, m) → O_2
14. Segment(B, O_2) → R
15. LaTeX(r, true, true) → text2
16. LaTeX(R, true, true) → text3
17. Midpoint(c) → G
18. Midpoint(a) → H
19. Midpoint(b) → I
20. Circle(G, H, I) → q
21. Segment(G, I) → s
22. Midpoint(s) → J
23. Segment(I, H) → a_1
24. Midpoint(a_1) → K
25. OrthogonalLine(K, a_1) → b_1
26. OrthogonalLine(J, s) → t
27. Intersect(t, b_1) → O_1
28. Segment(O_1, I) → c_1