筝形的面积

GeoGebra 命令及参数

1. Polygon(A, B, C) → poly1, c, f, b
2. Polygon(A, D, C) → poly2, c_1, a_1, d_1
3. Polygon(B, E, C) → poly3, c_2, b_1, e
4. Polygon(D, C, E) → poly4, e_1, d_2, c_3
5. Rotate(A, d * °, A) → A'
6. Rotate(B, d * °, A) → B'
7. Rotate(C, d * °, A) → C'
8. Polygon(A', B', C') → poly1', c', a', b'
9. Rotate(B, -1.0 * a * °, E) → B'_1
10. Rotate(E, -1.0 * a * °, E) → E'
11. Rotate(C, -1.0 * a * °, E) → C'_1
12. Polygon(B'_1, E', C'_1) → poly3', c'_1, b'_1, e'