Determine if Two Triangles are Similar Using Transformations by Mark Hampton

Determine if Two Triangles are Similar Using Transformations by Mark Hampton
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2015-01-17 03:06
This example demonstrates how to determine if two triangles are similar using transformations. Key mathematical concepts include the properties of similar triangles and transformations. Using GeoGebra commands such as If, Circle, Point, Line, Intersect, Polygon, OrthogonalLine, Segment, Dilate, Angle, Vector, etc., two triangles are constructed and transformed. Suitable for students at the middle school level and above to learn about similar triangles.

GeoGebra Commands & Parameters

  1. If(b < c, (b * 0.25), (c * 0.25)) → HandleRadius
  2. Circle(A, HandleRadius) → d
  3. Point(d) → Rotate
  4. Line(Rotate, A) → e
  5. Circle(A, b) → f
  6. Intersect(f, e, 2) → B
  7. Circle(B, a) → g
  8. Circle(A, c) → h
  9. Intersect(g, h, 2) → C
  10. Intersect(g, h, 1) → C'
  11. Polygon(A, B, C) → poly1, c_1, a_1, b_1
  12. OrthogonalLine(A, e) → i
  13. If(b < c, (b * 0.5), (c * 0.5)) → FlipHandleRadius
  14. Circle(A, FlipHandleRadius) → k
  15. Intersect(k, i) → E, F
  16. Segment(F, E) → j
  17. Point(j) → Reflect
  18. Polygon(A, B, C') → poly2, d_1, a_2, b_2
  19. Segment(Reflect, C) → l
  20. Segment(Reflect, C') → m
  21. Segment(A, Reflect) → n
  22. Segment(A, Rotate) → p
  23. Polygon(M, P, T) → poly3, p_1, m_1, n_1
  24. Dilate(A, dilation, A) → A'
  25. Dilate(B, dilation, A) → B'
  26. Dilate(C', dilation, A) → C''
  27. Polygon(A', B', C'') → poly2', c'', a', b'
  28. Dilate(A, dilation, A) → A'_1
  29. Dilate(B, dilation, A) → B'_1
  30. Dilate(C, dilation, A) → C'''
  31. Polygon(A'_1, B'_1, C''') → poly1', c'_1, a'_1, b'_1
  32. Circle(A, 0.2) → q
  33. Intersect(d, r, 1) → D
  34. Angle(Rotate, A, D) → α
  35. Vector(AStartValue, A) → u