演示对顶角相等

GeoGebra 命令及参数

1. Line(B, A) → a
2. Line(C, A) → b
3. Point(a) → D
4. Segment(B, D) → c
5. Point(b) → E
6. Segment(C, E) → d
7. Angle(B, A, C) → α
8. Angle(E, A, B) → β
9. Angle(D, A, E) → γ
10. Angle(C, A, D) → δ
11. Polygon(C, A, B) → poly1, b_1, c_1, a_1
12. Polygon(B, A, E) → poly2, e, b_2, a_2
13. Rotate(C, -red, A) → C'
14. Rotate(A, -red, A) → A'
15. Rotate(B, -red, A) → B'
16. Polygon(C', A', B') → poly1', b', c', a'
17. Rotate(B, -green, A) → B'_1
18. Rotate(A, -green, A) → A'_1
19. Rotate(E, -green, A) → E'
20. Polygon(B'_1, A'_1, E') → poly2', e', b'_1, a'_1
21. Angle(E', A, B'_1) → ζ
22. Angle(B', A, C') → ε