三角形内角和 by Sanjay Gulati

GeoGebra 命令及参数

1. Polygon(B, C, A) → poly1, c, a, b
2. Line(A, c) → L_1
3. Midpoint(b) → D
4. Midpoint(a) → E
5. Rotate(B, α, E) → A'
6. Rotate(C, α, E) → B'
7. Rotate(A, α, E) → C'
8. Polygon(A', B', C') → poly2, c', a', b'
9. Rotate(B, (-α), D) → A_1
10. Rotate(C, (-α), D) → B_1
11. Rotate(A, (-α), D) → C_1
12. Polygon(A_1, B_1, C_1) → poly3, c_1, a_1, b_1
13. Angle(C, B, A) → β
14. Angle(B, A, C) → γ
15. Angle(A, C, B) → δ
16. Angle(B', A', C') → ε
17. Angle(B_1, A_1, C_1) → ζ
18. Angle(A', C', B') → η
19. Angle(A_1, C_1, B_1) → θ
20. Angle(C', B', A') → ι
21. Angle(C_1, B_1, A_1) → κ
22. If(α ≟ 180°, A_1) → F
23. If(α ≟ 180°, A_1) → G
24. If(α ≟ 180°, A_1) → H