梯形的性质 by Andrea Morgan

GeoGebra 命令及参数

1. Segment(A, B) → a_2
2. Line(C, a_2) → b_2
3. Point(b_2) → D
4. Polygon(A, C, D, B) → P, a_1, a, d, b
5. Midpoint(D, B) → E
6. Line(A, B) → e
7. OrthogonalLine(D, e) → f
8. Intersect(f, e) → F
9. Midpoint(a_2) → L
10. Segment(A, D) → c
11. Segment(C, B) → g
12. Angle(B, C, D) → α
13. Angle(C, B, A) → β
14. Angle(C, D, A) → γ
15. Angle(B, A, D) → δ
16. Angle(A, C, D) → ε
17. Angle(C, D, B) → ζ
18. Angle(D, B, A) → η
19. Angle(B, A, C) → θ