任意多边形内角和:探究与验证

任意多边形内角和:探究与验证
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2023-09-11 18:20
该范例通过GeoGebra交互图形展示:随着多边形边数变化,内角和如何遵循固定规律,并引导学生回答三角形、十边形与一百边形的内角和问题。核心数学概念包括多边形的内角、内角和公式、从三角形分割得到的推理,以及基于角度测量/汇总的验证。作图要点体现为:利用Polygon构造多边形顶点集合,结合Point、Segment与Angle计算各内角;再通过Rotate、Dilate与Mirror进行位置或对称/复制相关的几何变换以完成分割或角度布局;用Intersect与Circle/CircleSector生成关键辅助几何元素(如构造参考点或扇形角度区域),并用Midpoint与若干条件If配合完成自动化逻辑;最后将各内角角度对象汇总(如allAng4/5/6)并在界面中呈现文本提问与结果(textQuestion、textAllIn等)。适合GR.6-8年级的几何探究课、课堂演示或分组活动,用于帮助学生理解并验证“内角和随边数变化”的规律。

GeoGebra 命令及参数

  1. Mirror(P1, yAxis) → P1'
  2. Mirror(P1', xAxis) → P1''
  3. Mirror(P1'', yAxis) → P1'''
  4. Polygon(P1, P1', P1'', P1''') → peep, p1, p1', p1'', p1'''
  5. SelectedIndex(ddMenu) → is
  6. Mirror(A, x = x(CEN)) → B
  7. Intersect(xAxis, yAxis) → O
  8. Circle(CEN, A) → c
  9. Point(c) → C
  10. Point(c) → D
  11. Point(c) → E
  12. Point(c) → F
  13. Polygon(If[is ≟ 1, {A, B, C, D}, is ≟ 2, {A, B, C, D, E}, {A, B, C, D, E, F}]) → poli
  14. Dilate(B, If[0 < aniSli ≤ 1, 1 - aniSli, 0], D) → B'
  15. Segment(B, B') → segmBD
  16. Angle(A, B, D) → allAng4
  17. Angle(D, A, B) → allAng5
  18. Angle(B, D, A) → allAng6
  19. Angle(D, B, C) → allAng1
  20. Angle(C, D, B) → allAng2
  21. Angle(B, C, D) → allAng3
  22. Dilate(A, If[0 < aniSli ≤ 1, 1 - aniSli, 0], D) → A'
  23. Segment(A, A') → segmAD
  24. Angle(E, A, D) → fiveAng1
  25. Angle(D, E, A) → fiveAng2
  26. Angle(A, D, E) → fiveAng3
  27. Dilate(F, If[0 < aniSli ≤ 1, 1 - aniSli, 0], D) → F'
  28. Segment(F, F') → segmFD
  29. Angle(F, A, D) → sixAng1
  30. Angle(D, F, A) → sixAng2
  31. Angle(A, D, F) → sixAng3
  32. Angle(E, F, D) → sixAng4
  33. Angle(D, E, F) → sixAng5
  34. Angle(F, D, E) → sixAng6
  35. Segment(G, H) → angBase3
  36. Segment(K, L) → angBase2
  37. Midpoint(I, J) → M1
  38. Midpoint(K, L) → M2
  39. Midpoint(G, H) → M3
  40. Segment(I, J) → angBase1
  41. Rotate(J, allAng1, M1) → J1
  42. Rotate(J1, allAng2, M1) → J2
  43. CircleSector(M1, J, J1) → allAng1Recap
  44. CircleSector(M1, J1, J2) → allAng2Recap
  45. CircleSector(M1, J2, I) → allAng3Recap
  46. Rotate(L, allAng4, M2) → L1
  47. Rotate(L1, allAng5, M2) → L2
  48. CircleSector(M2, L, L1) → allAng4Recap
  49. CircleSector(M2, L1, L2) → allAng5Recap
  50. CircleSector(M2, L2, K) → allAng6Recap
  51. Rotate(H, fiveAng1, M3) → H1
  52. Rotate(H1, fiveAng2, M3) → H2
  53. CircleSector(M3, H, H1) → fiveAng1Recap
  54. CircleSector(M3, H1, H2) → fiveAng2Recap
  55. CircleSector(M3, H2, G) → fiveAng3Recap
  56. If(is ≟ 2, H + (3, 0), L + (3, 0)) → M
  57. Midpoint(M, N) → M4
  58. Segment(M, N) → angBase4
  59. Rotate(N, sixAng1, M4) → N1
  60. Rotate(N1, sixAng2, M4) → N2
  61. CircleSector(M4, N, N1) → sixAng1Recap
  62. CircleSector(M4, N1, N2) → sixAng2Recap
  63. CircleSector(M4, N2, M) → sixAng3Recap
  64. Segment(P, Q) → angBase5
  65. Midpoint(P, Q) → M5
  66. Rotate(Q, sixAng4, M5) → Q1
  67. Rotate(Q1, sixAng5, M5) → Q2
  68. CircleSector(M5, Q, Q1) → sixAng4Recap
  69. CircleSector(M5, Q1, Q2) → sixAng5Recap
  70. CircleSector(M5, Q2, P) → sixAng6Recap
  71. Segment(M1, J1 + (0.5 * UnitVector[Segment[M1, J1]])) → div11
  72. Segment(M1, J2 + (0.5 * UnitVector[Segment[M1, J2]])) → div12
  73. Segment(M2, L1 + (0.5 * UnitVector[Segment[M2, L1]])) → div21
  74. Segment(M2, L2 + (0.5 * UnitVector[Segment[M2, L2]])) → div22
  75. Segment(M3, H1 + (0.5 * UnitVector[Segment[M3, H1]])) → div31
  76. Segment(M3, H2 + (0.5 * UnitVector[Segment[M3, H2]])) → div32
  77. Segment(M4, N1 + (0.5 * UnitVector[Segment[M4, N1]])) → div41
  78. Segment(M4, N2 + (0.5 * UnitVector[Segment[M4, N2]])) → div42
  79. Segment(M5, Q1 + (0.5 * UnitVector[Segment[M5, Q1]])) → div51
  80. Segment(M5, Q2 + (0.5 * UnitVector[Segment[M5, Q2]])) → div52
  81. circlePixels(C, 7 + (7 * pulsing), Corner[1], Corner[3], Corner[5]) → pulsingObject

AI 绘图提示语参考

绘制一个多边形内角和验证示意图。先画一个正方形作为参考,再画一个圆,在圆上取若干点,根据下拉菜单选择三点、四点或五点构成多边形。从多边形的一个顶点向其他顶点连线,将多边形分割成三角形,并标出每个内角。用圆弧表示每个角的度数,并汇总显示内角和。同时用动画滑块控制辅助线,展示从顶点到对边的动态连线,帮助理解多边形内角和与三角形分割的关系。
以上提示语为根据原始绘图命令整理而来,仅供参考。