梯形的面积 by croober

GeoGebra 命令及参数

1. Line(A, D) → a
2. Line(C_1, a) → b
3. Segment(A, D) → c
4. Segment(A, C_1) → d
5. Point(b) → D_1
6. Segment(D, D_1) → e
7. Segment(C_1, D_1) → f
8. Midpoint(d) → E
9. Midpoint(e) → F
10. Polygon(A, E, F, D) → poly1, a_1, e_1, f_1, b_1
11. Polygon(E, C_1, D_1, F) → poly2, e_2, c_1, d_1, f_2
12. Rotate(E, -(Rotate), F) → E'
13. Rotate(C_1, -(Rotate), F) → B
14. Rotate(D_1, -(Rotate), F) → C
15. Rotate(F, -(Rotate), F) → F'
16. Polygon(E', B, C, F') → poly2', e', c', d', f'
17. Midpoint(c) → G
18. Midpoint(c') → H
19. Point(poly2) → I
20. OrthogonalLine(I, c_1) → g
21. Intersect(g, c) → J
22. Segment(I, J) → h
23. Midpoint(h) → K
24. Midpoint(J, K) → L
25. Segment(J, K) → i