相似三角形中的比例 by John Springall

GeoGebra 命令及参数

1. Polygon(A, B, C) → P, c, a, b
2. Angle(P) → α_1, β_1, γ_1
3. Line(B, C) → d_1
4. Textfield(Answer) → InputBox2
5. Angle(A, C, B) → β
6. Angle(B, A, C) → α
7. Rotate(A, rotaterandom, H) → A'
8. Rotate(B, rotaterandom, H) → B'
9. Rotate(C, rotaterandom, H) → C'
10. Polygon(A', B', C') → P', c', a', b'
11. Dilate(A', scale) → A''
12. Dilate(B', scale) → B''
13. Dilate(C', scale) → C''
14. Polygon(A'', B'', C'') → P'', c'', a'', b''
15. Point(Circle[D, Segment[A'', B'']]) → E
16. Rotate(E + (Segment[B'', C''], 0), Angle[C'' - B''] + Angle[E - D] - Angle[B'' - A''], E) → F
17. Polygon(D, E, F) → poly1, f, d_2, e
18. Intersect(e, d_2) → G
19. Angle(D, G, E) → γ
20. Angle(G, E, D) → δ