等腰直角三角形(45-45-90)

等腰直角三角形(45-45-90)
几何画板及绘图内容加载中,请稍等……
2018-08-14 01:22
①本范例通过动态演示等腰直角三角形的性质,帮助学生直观理解其特点;②涉及核心数学概念包括等腰三角形、直角三角形、对称性、三角函数等;③作图要点运用了Circle(圆)、Segment(线段)、OrthogonalLine(垂线)、Rotate(旋转)、Angle(角度)、Ray(射线)、Intersect(交点)、Polygon(多边形)、Line(直线)、Point(点)、Dilate(缩放)、CircleSector(扇形)、Vector(向量)、Translate(平移)等GeoGebra命令和对象;④适合高中数学教学,用于几何作图与性质探究。

GeoGebra 命令及参数

  1. Circle(B, C) → c
  2. Segment(B, C) → a
  3. OrthogonalLine(C, a) → b
  4. Rotate(C, 45°, B) → C'
  5. Angle(C, B, C') → α
  6. Ray(B, C') → d
  7. Intersect(b, d) → A
  8. Segment(A, C) → e
  9. Segment(B, A) → f
  10. Polygon(B, C, A) → poly1, a_1, b_1, c_1
  11. Line(B, C) → h
  12. Point(h) → D
  13. Point(h) → E
  14. Ray(C, E) → i
  15. Point(i) → F
  16. Ray(C, F) → j
  17. Dilate(B, If[0 < g ≤ 1, 1 - g, 0], C) → B'
  18. Segment(B, B') → k
  19. Dilate(C, If[1 < g ≤ 2, 2 - g, 0], A) → C'_1
  20. Segment(C, C'_1) → l
  21. Circle(C, (0.15 * a)) → p
  22. Intersect(p, j, 1) → G
  23. Intersect(p, e, 1) → H
  24. Intersect(p, a, 1) → I
  25. Circle(A, (0.15 * a)) → q
  26. Circle(B, (0.15 * a)) → r
  27. Intersect(q, e, 1) → J
  28. Intersect(q, f, 1) → K
  29. CircleSector(C, H, I) → s
  30. Dilate(A, If[2 < g ≤ 3, 3 - g, 0], B) → A'
  31. Segment(A, A') → m
  32. CircleSector(A, K, J) → t
  33. Rotate(s, If[3.5 < g ≤ 4.5, ((-(g - 3.5)) * π / 2), -1.5707963267948966], C) → s'
  34. Dilate(A, If[5.5 < g ≤ 6.5, 6.5 - g, 0], B) → A'_1
  35. Vector(A, A'_1) → u
  36. Translate(t, u) → t'
  37. Rotate(B, If[4.5 < g ≤ 5.5, ((-(g - 4.5)) * π / 2), -1.5707963267948966], C) → B'_1
  38. Rotate(B', If[4.5 < g ≤ 5.5, ((-(g - 4.5)) * π / 2), -1.5707963267948966], C) → B''
  39. Segment(B'_1, B'') → k'
  40. Rotate(t', If[6.5 < g ≤ 7.5, (((-(g - 6.5)) * 5) * π / 4), -3.92699], B) → t''
  41. Dilate(A, If[7.5 < g ≤ 8.5, 8.5 - g, 0], C) → A'_2
  42. Vector(A, A'_2) → v
  43. Translate(t, v) → t'_1
  44. Rotate(t'_1, If[8.5 < g ≤ 9.5, (((-(g - 8.5)) * 3) * π / 4), -2.356194490192345], C) → d_1
  45. Dilate(A, If[9.5 < g ≤ 10.5, 10.5 - g, 0], C) → A'_3
  46. Vector(A, A'_3) → w
  47. Translate(t, w) → t'_2
  48. Rotate(t'_2, If[10.5 < g ≤ 11.5, ((-(g - 10.5)) * π / 2), -1.5707963267948966], C) → e_1