中位线到斜边的证明

GeoGebra 命令及参数

1. Midpoint(A, B) → C_1
2. Circle(C_1, B) → d
3. Point(d) → C
4. Polygon(B, C, A) → t1, a, b, d_1
5. Angle(A, C, B) → α
6. Segment(C, C_1) → f
7. Segment(A, C_1) → g
8. Segment(C_1, B) → h
9. Rotate(B, If[Animation < 10, (Animation * π / 10), π], C_1) → B'
10. Rotate(C, If[Animation < 10, (Animation * π / 10), π], C_1) → D'
11. Rotate(A, If[Animation < 10, (Animation * π / 10), π], C_1) → A'
12. Polygon(B', D', A') → t1', a', b', d'
13. Segment(C_1, D') → j
14. Angle(A', D', B') → β
15. Rotate(C, If[Animation ≤ 10, 0, If[10 < Animation < 20, ((Animation - 10) * π / 10), π]], C_1) → D'_1
16. Rotate(C_1, If[Animation ≤ 10, 0, If[10 < Animation < 20, ((Animation - 10) * π / 10), π]], C_1) → M
17. Segment(D'_1, M) → f'
18. Rotate(B, If[Animation ≤ 20, 0, If[20 < Animation < 30, (((Animation - 20) * 2) * π / 10), (2 * π)]], C_1) → B'_1
19. CircleArc(C_1, B, B'_1) → e
20. Midpoint(f) → D