Construction and Properties of the Steiner Point

Construction and Properties of the Steiner Point
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2018-05-23 06:39
①This example demonstrates how to construct the Steiner point of a triangle through geometric steps, revealing its relationships with the triangle's sides, circumcircle, and reflections. ②Core mathematical concepts include the definition of the Steiner point, mirror reflection (axial symmetry), the connection between hyperbolas and right triangles, and angle/segment ratio properties. ③Construction highlights: based on the summary, GeoGebra commands such as Segment, Rotate, Angle, Intersect, Polygon, and Circle are used to build triangle ABC, reflected points A', B', D', auxiliary circles, lines, and angle markers, finally intersecting to locate the Steiner point. ④Suitable for high school and above students or math enthusiasts to explore special point constructions, reflection transformations in geometry, and precise dynamic geometry software techniques.

GeoGebra Commands & Parameters

  1. Segment(A, B) → f
  2. Segment(B, C) → g
  3. Segment(C, A) → h
  4. Rotate(A, 60°, B) → A'
  5. Angle(A, B, A') → α
  6. Segment(A', C) → i
  7. Segment(A', B) → j
  8. Rotate(B, 60°, C) → B'
  9. Angle(B, C, B') → β
  10. Segment(C, B') → k
  11. Segment(A, B') → l
  12. Intersect(i, l) → D
  13. Angle(C, D, A) → γ
  14. Segment(B, D) → m
  15. Angle(A, D, B) → δ
  16. Segment(A, D) → n
  17. Segment(D, C) → p
  18. Rotate(D, 60°, B) → D'
  19. Angle(D, B, D') → ζ
  20. Polygon(B, A, 3) → poly1, s, t, a, E
  21. Polygon(A, C, 3) → poly2, b, c, d, F
  22. Circle(F, A, C) → e
  23. Circle(A', B, A) → c_1
  24. Segment(A, F) → q
  25. Segment(A', A) → r
  26. Segment(C, F) → f_1
  27. Rotate(G, 60°, B) → G'
  28. Angle(G, B, G') → ε
  29. Segment(B, G) → g_1
  30. Segment(A, G) → h_1
  31. Segment(G, C) → i_1
  32. Segment(G', G) → j_1
  33. Segment(A', G') → k_1
  34. Segment(G', B) → l_1