四边形中点分割矩形

四边形中点分割矩形
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2015-09-09 15:17
①本范例演示如何通过连接四边形一对对边中点的线将其分割成一个矩形;②涉及的核心数学概念包括中点、线段、旋转、交点等;③作图要点——从下方『构造摘要』提炼用到了Polygon(多边形)、Midpoint(中点)、Segment(线段)、Intersect(交点)、Point(点)、Rotate(旋转)、Angle(角度)等GeoGebra命令/对象;④适合高中阶段学习几何作图的学生使用。

GeoGebra 命令及参数

  1. Polygon(A, B, C, D) → poly1, a, b, c, d
  2. Midpoint(d) → F
  3. Midpoint(c) → G
  4. Midpoint(b) → H
  5. Segment(F, H) → e
  6. Intersect(OrthogonalLine[G, e], e) → J
  7. Point(h) → L
  8. Rotate(F, Angle[A, F, L], F) → F'
  9. Rotate(A, Angle[A, F, L], F) → A'
  10. Rotate(B, Angle[A, F, L], F) → B'
  11. Rotate(H, Angle[A, F, L], F) → H'_1
  12. Polygon(F', A', B', H'_1) → poly3, f', a', b', h'_1
  13. Midpoint(a') → E
  14. Intersect(OrthogonalLine[E, h'_1], h'_1) → I
  15. Point(f) → M
  16. Rotate(E, Angle[B', E, M], E) → E'
  17. Rotate(I, Angle[B', E, M], E) → I'
  18. Rotate(H'_1, Angle[B', E, M], E) → N
  19. Rotate(B', Angle[B', E, M], E) → B''
  20. Polygon(E', I', N, B'') → poly4, e', i', n, b''
  21. Polygon(L, E', I, F') → poly5, l, e'_1, i, f'_1
  22. Point(g) → K
  23. Rotate(F, Angle[D, F, K], F) → F'_1
  24. Rotate(H, Angle[D, F, K], F) → H'
  25. Rotate(C, Angle[D, F, K], F) → C'
  26. Rotate(D, Angle[D, F, K], F) → D'
  27. Polygon(F'_1, H', C', D') → poly2, f'_2, h', c', d'
  28. Rotate(J, Angle[D, F, K], F) → J'
  29. Rotate(G, Angle[D, F, K], F) → G'
  30. Point(p) → O
  31. Rotate(G', Angle[C', G', O], G') → G''
  32. Rotate(J', Angle[C', G', O], G') → J''
  33. Rotate(H', Angle[C', G', O], G') → H''
  34. Rotate(C', Angle[C', G', O], G') → C''
  35. Polygon(G'', J'', H'', C'') → poly6, g'', j'', h'', c''
  36. Polygon(K, F'_1, J', G') → poly7, k_1, f'_3, j', g'
  37. Segment(F, H) → m
  38. Segment(G, J) → q
  39. Segment(Midpoint[Segment[A, B]], Intersect[m, OrthogonalLine[Midpoint[Segment[A, B]], m]]) → r
  40. Angle(F, Intersect[m, OrthogonalLine[Midpoint[Segment[A, B]], m]], Midpoint[Segment[A, B]]) → α
  41. Angle(H, J, G) → β