梯形面积公式证明 by Jean Kraiwitchaicharoen

GeoGebra 命令及参数

1. Polygon(C, A, E) → poly1, e, c, a
2. Polygon(C, F, E) → poly2, e_1, c_1, f
3. Polygon(C, D, F) → poly3, f_1, c_2, d
4. Polygon(D, F, B) → poly4, b, d_1, f_2
5. Segment(C, A) → g
6. Segment(A, B) → h
7. Segment(C, D) → i
8. Segment(B, D) → j
9. Segment(C, E) → k
10. Segment(D, F) → l
11. Segment(C, F) → m
12. Angle(C, E, A) → α
13. Angle(B, F, D) → β
14. Vector(G, H) → u
15. Vector(I, J) → v
16. Vector(M, N) → n
17. Vector(O, P) → p
18. Vector(O, Q) → q
19. Vector(R, S) → w