Rotational Symmetry by Mr. Krebs

Rotational Symmetry by Mr. Krebs
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2018-01-04 08:14
This example demonstrates the phenomenon of a shape coinciding with its original position after rotation by a certain angle. It involves core mathematical concepts such as symmetry, rotation angles, and polygon construction. Key GeoGebra commands used include Segment, OrthogonalLine, Point, Intersect, Polygon, Circle, Line, Rotate, Mirror for constructing and transforming the图形. It is suitable for high school students learning geometric transformations and symmetry.

GeoGebra Commands & Parameters

  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. Polygon(C, D, B, A) → poly1, c_1, d_1, b_1, a_1
  8. Segment(C, B) → e
  9. Segment(D, A) → f
  10. Intersect(e, f) → E
  11. Polygon(F, G, 4) → poly2, f_1, g, h, i, H, I
  12. Segment(I, G) → j
  13. Segment(H, F) → k
  14. Intersect(j, k) → J
  15. Segment(K, L) → l
  16. Circle(K, L) → p
  17. Point(p) → M
  18. Segment(K, M) → m
  19. Line(M, l) → n
  20. Line(L, m) → q
  21. Intersect(n, q) → N
  22. Segment(M, L) → r
  23. Segment(N, K) → s
  24. Intersect(r, s) → O
  25. Polygon(M, N, L, K) → poly3, m_1, n_1, l_1, k_1
  26. Rotate(C, (-α), E) → C'
  27. Rotate(D, (-α), E) → D'
  28. Rotate(B, (-α), E) → B'
  29. Rotate(A, (-α), E) → A'
  30. Polygon(C', D', B', A') → poly1', c', d', b', a'
  31. Rotate(M, (-α), O) → M'
  32. Rotate(N, (-α), O) → N'
  33. Rotate(L, (-α), O) → L'
  34. Rotate(K, (-α), O) → K'
  35. Polygon(M', N', L', K') → poly3', m', n', l', k'
  36. Segment(P, Q) → t
  37. Segment(P, R) → e_1
  38. Line(Q, e_1) → g_1
  39. Line(R, t) → h_1
  40. Intersect(g_1, h_1) → S
  41. Polygon(P, R, S, Q) → poly4, p_1, r_1, s_1, q_1
  42. Segment(R, Q) → i_1
  43. Segment(S, P) → j_1
  44. Intersect(i_1, j_1) → T
  45. Rotate(P, (-α), T) → P'
  46. Rotate(R, (-α), T) → R'
  47. Rotate(S, (-α), T) → S'
  48. Rotate(Q, (-α), T) → Q'
  49. Polygon(P', R', S', Q') → poly4', p', r', s', q'
  50. Segment(U, V) → t_1
  51. Segment(U, W) → a_2
  52. Line(W, t_1) → b_2
  53. Point(b_2) → Z
  54. Segment(Z, V) → c_2
  55. Polygon(U, V, Z, W) → poly5, u, v, z, w
  56. Segment(W, V) → d_2
  57. Segment(Z, U) → e_2
  58. Intersect(d_2, e_2) → A_1
  59. Rotate(U, (-α), A_1) → U'
  60. Rotate(V, (-α), A_1) → V'
  61. Rotate(Z, (-α), A_1) → Z'
  62. Rotate(W, (-α), A_1) → W'
  63. Polygon(U', V', Z', W') → poly5', u', v', z', w'
  64. Line(B_1, C_1) → f_2
  65. Mirror(D_1, f_2) → E_1
  66. Polygon(D_1, B_1, E_1, C_1) → poly6, d_3, b_3, e_3, c_3
  67. Segment(D_1, E_1) → g_2
  68. Intersect(f_2, g_2) → F_1
  69. Rotate(D_1, (-α), F_1) → G_1
  70. Rotate(B_1, (-α), F_1) → H_1
  71. Rotate(E_1, (-α), F_1) → I_1
  72. Rotate(C_1, (-α), F_1) → J_1
  73. Polygon(G_1, H_1, I_1, J_1) → poly6', g_3, h_2, i_2, j_2
  74. Rotate(poly2, (-α), J) → poly2'

AI Drawing Prompt Reference

Draw a geometric figure demonstrating rotational symmetry. Construct a rectangle, a square, and a parallelogram, each with its diagonals intersecting at a center point. Rotate each polygon around its own center by the same angle so that the rotated image coincides with the original, showing symmetry. Use line segments to connect key vertices and keep construction lines visible to illustrate the process.
The prompt above was compiled from the original drawing commands and is for reference only.