梯形的面积 by kennedyc6

GeoGebra 命令及参数

1. Segment(A, D) → a
2. Segment(C, D) → b
3. Segment(B, C) → c
4. Segment(B, A) → d
5. Midpoint(B, A) → E
6. Midpoint(C, D) → F
7. Segment(E, F) → e
8. Polygon(E, B, C, F) → top, e_1, b_1, c_1, f
9. Polygon(E, A, D, F) → poly2, e_2, a_1, d_1, f_1
10. Rotate(C, 180*°, F) → C'
11. Rotate(F, 180*°, F) → F'
12. Mirror(E, F) → E'
13. Mirror(B, F) → B'
14. Mirror(C, F) → C'_1
15. Mirror(F, F) → F'_1
16. Polygon(E', B', C'_1, F'_1) → top', e', b', c'_1, f'_1