等角定理动态演示

等角定理动态演示
几何画板及绘图内容加载中,请稍等……
2017-04-02 08:15
①本范例动态演示连接三角形顶点与外心的线段所形成的等角定理;②涉及核心数学概念包括等角定理、三角形外心、圆的性质;③作图要点提炼自构造摘要,使用了 Rotate(旋转)、Segment(线段)、LineBisector(角平分线)、Circle(圆)等 GeoGebra 命令/对象;④适合高中数学教学,用于理解三角形外心与等角定理的关联。

GeoGebra 命令及参数

  1. Rotate(A, (-((a * π / 180))), B) → A'
  2. Angle(A', B, A) → α
  3. Segment(A, B) → f
  4. Ray(B, A') → g
  5. Point(g) → C
  6. Segment(A, C) → h
  7. Segment(B, C) → i
  8. LineBisector(i) → j
  9. LineBisector(f) → k
  10. Intersect(j, k) → D
  11. Circle(D, B) → c
  12. Segment(D, C) → l
  13. Line(A, B) → m
  14. OrthogonalLine(C, m) → n
  15. Intersect(m, n) → E
  16. Min({l, h, i}) → b
  17. Circle(C, (0.3 * b)) → d
  18. Intersect(d, h, 1) → F
  19. Intersect(d, l, 1) → G
  20. Angle(D, C, B) → β
  21. CircleSector(C, G, F) → e
  22. Angle(E, C, A) → γ
  23. Angle(B, C, D) → δ
  24. Intersect(d, i, 1) → H
  25. CircleSector(C, H, G) → p
  26. Angle(E, A, C) → ε
  27. CircleSector(C, G, H) → q
  28. Dilate(D, If[0 < o ≤ 1, 1 - o, 0], C) → D'
  29. Segment(D, D') → r
  30. Rotate(C, If[1 < o ≤ 3, ((o - 1) * π), (2 * π)], D) → C'
  31. CircleArc(D, C, C') → s
  32. Dilate(C, If[3 < o ≤ 4, 4 - o, 0], E) → C'_1
  33. Dilate(B, If[3 < o ≤ 4, 4 - o, 0], E) → B'
  34. Segment(B, B') → t
  35. Segment(C, C'_1) → f_1
  36. Angle(C, E, B) → ζ
  37. CircleArc(C, G, F) → c_1
  38. Angle(F, C, G) → θ
  39. Rotate(e, If[5 < o ≤ 6, ((o - 5) * β), β], C) → e'
  40. Rotate(p, If[5 < o ≤ 6, ((-(o - 5)) * θ), (-θ)], C) → p'
  41. CircleArc(C, H, G) → d_1
  42. Point(f_1) → I
  43. Midpoint(A, B) → J
  44. Segment(A, E) → g_1
  45. Segment(A, J) → h_1
  46. Angle(I, C, H) → κ
  47. Rotate(q, If[5 < o ≤ 6, ((-(o - 5)) * κ), (-κ)], C) → q'
  48. CircleArc(C, G, H) → e_1
  49. CircleSector(C, F, G) → k_1
  50. Angle(G, C, H) → μ
  51. Rotate(k_1, If[5 < o ≤ 6, ((o - 5) * μ), μ], C) → p_1
  52. CircleArc(C, F, G) → q_1
  53. Polygon(A, B, C) → poly1, c_2, a_1, b_1
  54. Min(f, i) → u
  55. Circle(B, (0.2 * u)) → r_1
  56. Intersect(r_1, f) → K,
  57. Intersect(r_1, i) → L,
  58. CircleSector(B, L, K) → s_1