平行四边形性质演示 by David T

GeoGebra 命令及参数

1. Segment(A, B) → d_1
2. Line(C, d_1) → b_2
3. Point(b_2) → D
4. Polygon(A, D, B) → P, a, b, d
5. Midpoint(D, B) → E
6. Rotate(A, (-rotateΔ), E) → A'
7. Rotate(C, (-rotateΔ), E) → C'
8. Rotate(D, (-rotateΔ), E) → D'
9. Rotate(B, (-rotateΔ), E) → B'
10. Polygon(A', D', B') → P', c, e, f
11. Line(A, B) → e_1
12. OrthogonalLine(D, e_1) → f_3
13. Intersect(f_3, e_1) → F
14. Midpoint(B', A') → G
15. Midpoint(D', C') → H
16. If(rotateΔ ≥ 0°, H) → I
17. If(rotateΔ > 0°, H) → J
18. If(rotateΔ > 0°, G) → K
19. Midpoint(d_1) → M
20. Angle(B', A', D') → γ
21. Angle(B, A, D) → δ
22. Angle(D, B, A) → ζ
23. Angle(D', B', A') → α
24. Angle(A, D, B) → β
25. Angle(A', D', B') → ε
26. Segment(D', A') → c_1
27. Segment(A, D) → a_1
28. Segment(B', A') → f_1
29. Segment(A, D) → a_2
30. Segment(D', A') → c_2
31. Segment(B', A') → f_2
32. Segment(A, B) → d_2
33. Segment(D, E) → g
34. Segment(B, E) → g_1
35. Segment(A, E) → h
36. Segment(A', E) → h_1
37. Angle(E, A, D) → η
38. Angle(B, A, E) → θ
39. Angle(D, A', E) → ι
40. Angle(E, A', B) → κ
41. Angle(A, D, A') → λ
42. Angle(A', B, A) → μ