梯形的面积 by James Pearce

GeoGebra 命令及参数

1. Line(C, B) → b_2
2. Line(A, b_2) → c
3. Point(c) → D
4. Polygon(A, B, C, D) → poly1, a_1, b_1, c_1, d
5. Midpoint(c_1) → E
6. Rotate(A, α, E) → A'
7. Rotate(B, α, E) → B'
8. Rotate(C, α, E) → C'
9. Rotate(D, α, E) → D'
10. Polygon(A', B', C', D') → poly1', a', b', c', d'
11. OrthogonalLine(A, b_1) → e
12. Intersect(e, b_1) → F
13. Circle(B, (a_3 * (d + b_1))) → f
14. Line(B, b_1) → g
15. Intersect(f, g) → G, H
16. Vector(B, F) → u
17. Vector(F, A) → v
18. Translate(H, u) → H'
19. Vector(H, H') → w
20. Translate(H', v) → H''
21. Vector(H', H'') → h_2
22. Polygon(H, H', H'') → poly2, h'', h_1, h'
23. Polygon(A, F, C, D) → poly3, a_2, f_1, c_2, d_1
24. Segment(A, F) → h
25. Circle(A, 0.5) → k
26. Intersect(k, e, 2) → I
27. Circle(F, 0.5) → p
28. Intersect(p, b_2) → J, K
29. Vector(F, H') → j
30. Vector(F, A) → l
31. Translate(K, l) → K'
32. Vector(K, K') → m
33. Translate(I, j) → I'
34. Vector(I, I') → n
35. Segment(K', K) → h_4
36. Vector(A, D) → s
37. Translate(I, s) → I'_1
38. Vector(I, I'_1) → t
39. Segment(I, I'_1) → a
40. Segment(I'_1, I') → b
41. Line(B, h) → g_1
42. Circle(B, 0.5) → k_1
43. Intersect(k_1, g_1, 2) → L
44. Vector(B, C) → u_1
45. Translate(L, u_1) → L'
46. Vector(L, L') → v_1
47. Segment(L, L') → b_3