多边形面积概览

GeoGebra 命令及参数

1. Polygon(A, B, C) → poly1, c, a, b
2. Line(A, B) → trLine1
3. Line(C, A) → trLine2
4. OrthogonalLine(C, trLine1) → d
5. Intersect(trLine1, d) → TrH1
6. Segment(C, TrH1) → trH1
7. OrthogonalLine(B, trLine2) → f
8. Intersect(trLine2, f) → TrH2
9. Segment(B, TrH2) → trH2
10. Segment(B, TrH1) → trBseg1
11. Segment(A, TrH1) → trBseg2
12. Segment(C, TrH2) → trBseg3
13. Segment(A, TrH2) → trBseg4
14. Text("h", Midpoint[trH1]) → trHText1
15. Text("h", Midpoint[trH2]) → trHText2
16. Text("b", Midpoint[c]) → trBText1
17. Text("b", Midpoint[b]) → trBText2
18. Line(D, E) → pLine
19. Line(F, E) → pLine2_1
20. Line(F, pLine) → pLine2
21. Line(D, pLine2_1) → pLine3
22. Intersect(pLine2, pLine3) → G
23. Polygon(D, E, F, G) → poly2, d_1, e_1, f_1, g
24. OrthogonalLine(F, pLine) → h
25. Intersect(pLine, h) → PH1
26. Segment(F, PH1) → pH1
27. Segment(E, PH1) → pBseg1
28. Segment(D, PH1) → pBseg2
29. OrthogonalLine(F, pLine3) → i
30. Intersect(pLine3, i) → PH2
31. Segment(PH2, F) → pH2
32. Segment(PH2, G) → pBseg3
33. Segment(D, PH2) → pBseg4
34. Text("h", Midpoint[pH1]) → pHText1
35. Text("b", Midpoint[D, E]) → pBText1
36. Text("h", Midpoint[pH2]) → pHText2
37. Line(H, I) → tLine1
38. Ray(J, J + Vector[I, H]) → tRay
39. Point(tRay) → K
40. Polygon(H, I, J, K) → poly3, h_1, i_1, j, k
41. OrthogonalLine(J, tLine1) → l
42. Intersect(l, tLine1) → TH
43. Segment(J, TH) → th
44. Text("h", Midpoint[th]) → tHText
45. Text("a", Midpoint[H, I]) → tAText
46. Text("b", Midpoint[K, J]) → tBText
47. Segment(TH, I) → tBseg1
48. Segment(H, TH) → tBseg2
49. Text("b", Midpoint[E, F]) → pBText2