四边形旋转对称性探究:正方形与风筝形

四边形旋转对称性探究:正方形与风筝形
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2017-12-12 14:42
所属专题 Rotational Symmetry 1
本范例演示了四边形(特别是正方形和风筝形)在旋转与镜像变换下的对称性质。核心数学概念包括旋转对称、轴对称、几何变换以及多边形的基本性质。作图要点:利用GeoGebra的Segment、OrthogonalLine、Point、Intersect、Polygon、Circle、Line、Rotate、Mirror、PointIn等命令,构造了正方形及其旋转后的副本,并涉及风筝形等四边形,通过旋转和镜像操作展示其对称性。适合中学几何教学,帮助学生直观理解旋转对称和轴对称的概念,以及不同四边形对称性的差异。

GeoGebra 命令及参数

  1. Segment(A, B) → a
  2. OrthogonalLine(A, a) → b
  3. OrthogonalLine(B, a) → c
  4. Point(b) → C
  5. OrthogonalLine(C, b) → d
  6. Intersect(c, d) → D
  7. Segment(C, B) → e
  8. Segment(D, A) → f
  9. Intersect(e, f) → E
  10. Polygon(F, G, 4) → poly2, f_1, g, h, i, H, I
  11. Segment(I, G) → j
  12. Segment(H, F) → k
  13. Intersect(j, k) → J
  14. Segment(K, L) → l
  15. Circle(K, L) → p
  16. Point(p) → M
  17. Segment(K, M) → m
  18. Line(M, l) → n
  19. Line(L, m) → q
  20. Intersect(n, q) → N
  21. Segment(M, L) → r
  22. Segment(N, K) → s
  23. Intersect(r, s) → O
  24. Rotate(C, (-α), E) → C'
  25. Rotate(D, (-α), E) → D'
  26. Rotate(B, (-α), E) → B'
  27. Rotate(A, (-α), E) → A'
  28. Polygon(C', D', B', A') → poly1', c', d', b', a'
  29. Rotate(M, (-α), O) → M'
  30. Rotate(N, (-α), O) → N'
  31. Rotate(L, (-α), O) → L'
  32. Rotate(K, (-α), O) → K'
  33. Polygon(M', N', L', K') → poly3', m', n', l', k'
  34. Segment(P, Q) → t
  35. Segment(P, R) → e_1
  36. Line(Q, e_1) → g_1
  37. Line(R, t) → h_1
  38. Intersect(g_1, h_1) → S
  39. Segment(R, Q) → i_1
  40. Segment(S, P) → j_1
  41. Intersect(i_1, j_1) → T
  42. Rotate(P, (-α), T) → P'
  43. Rotate(R, (-α), T) → R'
  44. Rotate(S, (-α), T) → S'
  45. Rotate(Q, (-α), T) → Q'
  46. Polygon(P', R', S', Q') → poly4', p', r', s', q'
  47. Segment(U, V) → t_1
  48. Line(W, t_1) → b_2
  49. Point(b_2) → Z
  50. Segment(W, V) → d_2
  51. Segment(Z, U) → e_2
  52. Intersect(d_2, e_2) → A_1
  53. Rotate(U, (-α), A_1) → U'
  54. Rotate(V, (-α), A_1) → V'
  55. Rotate(Z, (-α), A_1) → Z'
  56. Rotate(W, (-α), A_1) → W'
  57. Line(B_1, C_1) → f_2
  58. Mirror(D_1, f_2) → E_1
  59. Segment(D_1, E_1) → g_2
  60. Intersect(f_2, g_2) → F_1
  61. Rotate(D_1, (-α), F_1) → G_1
  62. Rotate(B_1, (-α), F_1) → H_1
  63. Rotate(E_1, (-α), F_1) → I_1
  64. Rotate(C_1, (-α), F_1) → J_1
  65. Polygon(G_1, H_1, I_1, J_1) → poly6', g_3, h_2, i_2, j_2
  66. Rotate(poly2, (-α), J) → poly2'
  67. Intersect(h, i) → L_1
  68. PointIn(poly2') → K_1