两条直线被截线所截

两条直线被截线所截
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2016-01-12 00:58
①本范例演示两条直线被截线所截形成的几何图形与角度关系;②涉及核心数学概念包括平行线性质、同位角、内错角、同旁内角等;③作图要点运用了 Rotate(旋转)、Angle(角度)、Line(直线)、Point(点)、Intersect(交点)、Midpoint(中点)等 GeoGebra 命令与对象;④适合初中及以上学生学习几何定理与证明,也可用于高中解析几何教学。

GeoGebra 命令及参数

  1. Rotate(A, (-α), B) → C
  2. Angle(C, B, A) → β
  3. Line(B, C) → a
  4. Line(A, B) → b
  5. Point(b) → D
  6. Rotate(B, (-γ), D) → E
  7. Angle(E, D, B) → δ
  8. Line(D, E) → c
  9. Point(a) → F
  10. Point(c) → G
  11. Angle(A, B, F) → ε
  12. Angle(F, B, D) → ζ
  13. Angle(D, B, C) → η
  14. Point(b) → H
  15. Angle(B, D, G) → θ
  16. Angle(G, D, H) → ι
  17. Angle(H, D, E) → κ
  18. Point(a) → I
  19. Point(c) → J
  20. Point(b) → K
  21. Point(b) → L
  22. Intersect(β, a, 1) → P
  23. Point(a) → Q
  24. Midpoint(L, Q) → M
  25. Intersect(ε, a, 1) → N
  26. Point(a) → O
  27. Intersect(ζ, b, 1) → S
  28. Intersect(η, b, 1) → T
  29. Intersect(ζ, b, 1) → U
  30. Intersect(ζ, b, 1) → V
  31. Intersect(ζ, b, 1) → W
  32. Intersect(ζ, b, 1) → Z
  33. Intersect(ζ, b, 1) → A_1
  34. Intersect(ζ, b, 1) → B_1
  35. Point(b) → R
  36. Point(b) → C_1
  37. Point(c) → D_1
  38. Point(b) → E_1
  39. Point(c) → F_1
  40. Midpoint(L, O) → G_1
  41. Midpoint(O, R) → H_1
  42. Midpoint(R, Q) → I_1
  43. Midpoint(C_1, F_1) → J_1
  44. Midpoint(F_1, E_1) → K_1
  45. Midpoint(E_1, D_1) → L_1
  46. Midpoint(D_1, C_1) → M_1