四边形周长

GeoGebra 命令及参数

1. Polygon(A, B, C, D) → q1, a, b, c, d
2. Line(A, D) → f
3. Line(D, C) → g
4. Point(f) → E
5. Point(f) → F
6. Point(g) → G
7. Angle(B, A, E) → α
8. Angle(F, D, C) → β
9. Angle(G, C, B) → γ
10. Rotate(B, If[0 ≤ k < 1, (-((k * γ))), (-γ)], C) → B'
11. Rotate(C, If[0 ≤ k < 1, (-((k * γ))), (-γ)], C) → C'
12. Segment(B', C') → b'
13. Rotate(C, If[1 ≤ k ≤ 2, ((-(k - 1)) * β)], D) → C'_1
14. Rotate(D, If[1 ≤ k ≤ 2, ((-(k - 1)) * β)], D) → D'
15. Segment(C'_1, D') → c'
16. Rotate(A, If[1 ≤ k ≤ 2, ((k - 1) * α)], A) → A'
17. Rotate(B, If[1 ≤ k ≤ 2, ((k - 1) * α)], A) → B'_1
18. Segment(A', B'_1) → a'
19. Rotate(B', If[1 ≤ k ≤ 2, ((-(k - 1)) * β)], D) → B''
20. Rotate(C', If[1 ≤ k ≤ 2, ((-(k - 1)) * β)], D) → C''
21. Segment(B'', C'') → b''
22. OrthogonalLine(B'_1, a') → h
23. OrthogonalLine(B'', b'') → i
24. Point(h) → H
25. Line(H, d) → j
26. Intersect(i, j) → I
27. Segment(H, I) → l
28. Perimeter(q1) → perimeterq1
29. PointIn(q1) → Pointq1