30-60-90 直角三角形探索

30-60-90 直角三角形探索
几何画板及绘图内容加载中,请稍等……
2019-06-26 09:42
本范例演示30-60-90直角三角形的性质。核心数学概念包括三角函数和相似三角形。通过旋转、角度测量、线段构造等GeoGebra命令,学生可以直观地理解该三角形的边长比。适合初中及以上学生学习几何作图和三角函数。

GeoGebra 命令及参数

  1. Ray(B, C) → f
  2. OrthogonalLine(C, f) → g
  3. Rotate(C, π / 3, B) → B'
  4. Angle(C, B, B') → α
  5. Ray(B, B') → h
  6. Intersect(g, h) → A
  7. Segment(B, C) → i
  8. Segment(C, A) → j
  9. Segment(B, A) → k
  10. Polygon(B, C, A) → poly1, c_1, a, b
  11. Circle(A, (0.2 * i)) → e
  12. Intersect(e, k) → D,
  13. Intersect(e, j) → E,
  14. CircleSector(A, D, E) → d
  15. Dilate(A, If[0 < l ≤ 1, 1 - l, 0], B) → C'
  16. Vector(A, C') → u
  17. Translate(d, u) → d'
  18. Rotate(d', If[1 < l ≤ 2, (((l - 1) * 2) * π / 3), (2 * π / 3)], B) → d''
  19. Dilate(A, If[2 < l ≤ 3, 3 - l, 0], B) → C'_1
  20. Vector(A, C'_1) → v
  21. Translate(d, v) → d'_1
  22. Rotate(d'_1, If[3 < l ≤ 4, (((-(l - 3)) * 7) * π / 6), (-7 * π / 6)], B) → p
  23. Dilate(A, If[4 < l ≤ 5, 5 - l, 0], C) → C'_2
  24. Vector(A, C'_2) → w
  25. Translate(d, w) → d'_2
  26. Dilate(A, If[6 < l ≤ 7, 7 - l, 0], C) → C'_3
  27. Vector(A, C'_3) → m
  28. Translate(d, m) → d'_3
  29. Rotate(d'_2, If[5 < l ≤ 6, ((-(l - 5)) * π / 2), ((-π)) / 2], C) → q
  30. Rotate(d'_3, If[7 < l ≤ 8, (((l - 7) * 4) * π / 3), (4 * π / 3)], C) → r
  31. Dilate(A, If[8 < l ≤ 9, 9 - l, 0], C) → C'_4
  32. Vector(A, C'_4) → n
  33. Translate(d, n) → d'_4
  34. Rotate(d'_4, If[9 < l ≤ 10, (((l - 9) * 7) * π / 6), (7 * π / 6)], C) → s
  35. Midpoint(B, A) → F
  36. Dilate(B, If[10 < l ≤ 11, 11 - l, 0], C) → A'
  37. Segment(B, A') → t
  38. Rotate(B, If[11 < l ≤ 12, ((l - 11) * π / 3), π / 3], B) → A'_1
  39. Rotate(A', If[11 < l ≤ 12, ((l - 11) * π / 3), π / 3], B) → A''
  40. Segment(A'_1, A'') → t'
  41. Dilate(B, If[12 < l ≤ 13, 13 - l, 0], F) → A'_2
  42. Vector(B, A'_2) → u_1
  43. Translate(B, u_1) → A'_3
  44. Translate(A', u_1) → A''_1
  45. Segment(A'_3, A''_1) → t'_1
  46. Rotate(A'_3, If[13 < l ≤ 14, ((l - 13) * π / 3), π / 3], F) → G
  47. Rotate(A''_1, If[13 < l ≤ 14, ((l - 13) * π / 3), π / 3], F) → H
  48. Segment(G, H) → f_1