平行四边形与梯形面积计算

GeoGebra 命令及参数

1. Segment(A, B) → f
2. Segment(A, C) → g
3. Line(C, f) → h_2
4. Line(B, g) → i
5. Intersect(h_2, i) → D
6. Segment(C, D) → j
7. Segment(D, B) → k
8. OrthogonalLine(B, f) → l
9. OrthogonalLine(C, h_2) → m
10. Line(A, B) → n
11. Intersect(m, n) → E
12. Intersect(h_2, l) → F
13. Intersect(h_2, l) → G
14. Segment(B, G) → p
15. Segment(G, D) → q
16. Intersect(m, n) → H
17. Segment(H, C) → r
18. Segment(H, A) → s
19. OrthogonalLine(A, f) → t
20. Intersect(t, j) → I
21. Segment(I, C) → a
22. Point(f) → J
23. OrthogonalLine(J, f) → b
24. Intersect(b, h_2) → K
25. Intersect(h_2, t) → L
26. Circle(K, a) → d
27. Intersect(d, h_2, 1) → M
28. Polygon(M, K, J) → poly2, j_1, m_1, k_1
29. Segment(D, L) → e
30. Segment(L, C) → f_1
31. Segment(A, L) → c
32. Segment(A, D) → g_1
33. Segment(A, L) → h_3
34. Polygon(A, D, C) → poly1, c_1, a_1, d_1
35. Polygon(A, D, B) → poly3, b_1, a_2, d_2
36. OrthogonalLine(D, f) → h_1
37. Intersect(h_1, f) → N
38. Segment(N, D) → i_1
39. Point(e) → O
40. Segment(O, D) → l_1
41. Segment(A, O) → n_1
42. Polygon(A, D, O) → poly4, o, a_3, d_3
43. Midpoint(k) → P
44. Polygon(B, A, O, D) → poly5, b_2, a_4, o_1, d_4
45. Rotate(B, (-α), P) → B'
46. Rotate(A, (-α), P) → A'
47. Rotate(O, (-α), P) → O'
48. Rotate(D, (-α), P) → D'
49. Polygon(B', A', O', D') → poly5', b', a', o', d'