七边形外角的旋转与和

七边形外角的旋转与和
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2015-10-28 01:48
本范例演示七边形(七条边)的外角旋转现象,通过旋转操作直观展示外角的形成过程。外角是延长多边形一边所形成的外部角度,与内角互为补角。核心数学概念包括:①多边形外角和恒等于360度的定理;②外角与内角的关系;③旋转角度的累加。作图要点使用GeoGebra的Rotate旋转命令构造各顶点外角,用Polygon创建七边形,用Angle测量角度,并用Ray绘制外角的边。学生可通过拖动点A或使用滑块观察外角α、β、γ等的动态变化,验证外角和始终为360度。适合初中数学课堂、多边形角度性质教学或作为几何直观演示素材。

GeoGebra 命令及参数

  1. Circle(A, 8 - a) → c
  2. Point(c) → B
  3. Line(A, B) → b
  4. Rotate(B, 51.7°, A) → B'
  5. Angle(B, A, B') → α
  6. Rotate(B', 51.7°, A) → B''
  7. Angle(B', A, B'') → β
  8. Rotate(B'', 51.7°, A) → B'''
  9. Angle(B'', A, B''') → γ
  10. Rotate(B''', 51.7°, A) → C
  11. Angle(B''', A, C) → δ
  12. Rotate(C, 51.7°, A) → C'
  13. Angle(C, A, C') → ε
  14. Rotate(C', 51.7°, A) → C''
  15. Angle(C', A, C'') → ζ
  16. CircleArc(A, B, B') → d
  17. CircleArc(A, B', B'') → e
  18. CircleArc(A, B'', B''') → f
  19. CircleArc(A, B''', C) → g
  20. CircleArc(A, C, C') → h
  21. CircleArc(A, C', C'') → k
  22. CircleArc(A, C'', B) → p
  23. Point(d) → D
  24. Point(e) → E
  25. Point(f) → F
  26. Point(g) → G
  27. Point(h) → H
  28. Point(k) → I
  29. Point(p) → J
  30. Ray(D, E) → i
  31. Ray(E, F) → j
  32. Ray(F, G) → l
  33. Ray(G, H) → m
  34. Ray(H, I) → n
  35. Ray(I, J) → q
  36. Ray(J, D) → r
  37. Circle(D, 1.5) → s
  38. Circle(E, 1.5) → t
  39. Circle(F, 1.5) → c_1
  40. Circle(G, 1.5) → d_1
  41. Circle(H, 1.5) → e_1
  42. Circle(I, 1.5) → f_1
  43. Circle(J, 1.5) → g_1
  44. Intersect(c_1, j, 2) → K
  45. Intersect(c_1, l, 1) → L
  46. Intersect(d_1, l, 2) → M
  47. Intersect(d_1, m, 1) → N
  48. Intersect(e_1, m, 2) → O
  49. Intersect(e_1, n, 1) → P
  50. Intersect(f_1, n, 2) → Q
  51. Intersect(f_1, q, 1) → R
  52. Intersect(g_1, q, 2) → S
  53. Intersect(g_1, r, 1) → T
  54. Intersect(s, r, 2) → U
  55. Intersect(s, i, 1) → V
  56. Intersect(t, j, 1) → W
  57. Intersect(t, i, 2) → Z
  58. CircleSector(F, K, L) → h_1
  59. CircleSector(G, M, N) → k_1
  60. CircleSector(H, O, P) → p_1
  61. CircleSector(I, Q, R) → q_1
  62. CircleSector(J, S, T) → r_1
  63. CircleSector(D, U, V) → s_1
  64. CircleSector(E, Z, W) → t_1
  65. Polygon(G, H, I, J, D, E, F) → poly1, g_2, h_2, i_1, j_1, d_2, e_2, f_2