三角形四心共点演示

三角形四心共点演示
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2019-11-14 02:36
①本范例演示了三角形中四个重要点(重心、垂心、内心、外心)的共点性;②涉及的核心数学概念包括三角形的几何性质、四心定理、解析几何作图;③作图要点提炼自GeoGebra命令:使用Line(线)、Segment(线段)、OrthogonalLine(垂线)、Intersect(交点)、Midpoint(中点)、Angle(角)、AngularBisector(角平分线)、LineBisector(线段平分线)等命令,构建了三角形的顶点、边、高、中线、角平分线及圆;④适合高中及以上数学学习者,用于理解三角形核心几何性质及作图方法。

GeoGebra 命令及参数

  1. Line(A, B) → LineAB
  2. Line(B, C) → LineBC
  3. Line(C, A) → SegAC
  4. Segment(B, A) → SegAB
  5. Segment(A, C) → SegAC_1
  6. Segment(C, B) → SegBC
  7. OrthogonalLine(A, LineBC) → f
  8. OrthogonalLine(C, LineAB) → g
  9. OrthogonalLine(B, SegAC) → h
  10. Intersect(SegAC, h) → D
  11. Intersect(g, LineAB) → F
  12. Intersect(LineBC, f) → G
  13. Segment(B, D) → AltitudeBD
  14. Segment(A, G) → AltitudeAG
  15. Segment(F, C) → AltitudeFC
  16. Midpoint(B, C) → H
  17. Midpoint(B, A) → I
  18. Midpoint(A, C) → J
  19. Segment(I, C) → MedianCI
  20. Segment(B, J) → MedianBJ
  21. Segment(A, H) → MedianAH
  22. Angle(A, G, B) → α
  23. Angle(B, D, C) → β
  24. Angle(C, F, A) → γ
  25. Segment(A, I) → AI
  26. Segment(I, B) → BI
  27. Segment(B, H) → BH
  28. Segment(H, C) → CH
  29. Segment(A, J) → AJ
  30. Segment(J, C) → CJ
  31. Intersect(MedianCI, MedianBJ) → E
  32. Intersect(AltitudeBD, AltitudeAG) → K
  33. AngularBisector(B, C, A) → i
  34. AngularBisector(C, A, B) → j
  35. AngularBisector(A, B, C) → k
  36. Intersect(j, LineBC) → L
  37. Intersect(LineAB, i) → M
  38. Intersect(k, SegAC) → P
  39. Segment(B, P) → AngBisBP
  40. Segment(C, M) → AngBisCM
  41. Segment(L, A) → AngBisAL
  42. Intersect(AngBisBP, AngBisCM) → InCenterN
  43. LineBisector(SegAC_1) → l
  44. LineBisector(SegAB) → m
  45. LineBisector(SegBC) → n
  46. Intersect(LineBC, n) → N
  47. Intersect(LineAB, m) → O
  48. Intersect(SegAC, l) → Q
  49. Intersect(l, m) → R
  50. Segment(R, Q) → PerpBisPQ
  51. Segment(R, N) → PerpBisRN
  52. Segment(R, O) → PerpBisOR
  53. Angle(R, Q, C) → δ
  54. Angle(R, N, B) → ε
  55. Angle(R, O, A) → ζ
  56. Line(N, R) → p
  57. Line(Q, R) → q
  58. Line(R, O) → r