三角形面积公式的几何剪拼证明：三角形面积等于底乘高除以二

GeoGebra 命令及参数

1. Polygon(A, B, C) → t1, c, a, b
2. OrthogonalLine(C, c) → f
3. Intersect(f, c) → H
4. Midpoint(C, H) → D
5. Segment(C, D) → g
6. Segment(D, H) → h
7. Line(D, c) → i
8. Intersect(i, a) → E
9. Intersect(i, b) → F
10. Polygon(C, F, E) → t2, e, c_1, f_1
11. Polygon(A, B, E, F) → q1, a_1, b_1, e_1, f_2
12. Rotate(C, (-α), E) → C'_1
13. Rotate(F, (-α), E) → F'_1
14. Rotate(E, (-α), E) → E'_1
15. Polygon(C'_1, F'_1, E'_1) → t2'_1, e'_1, c'_1, f'_1
16. Rotate(D, (-α), E) → D'
17. Segment(C'_1, D') → j