Vertical Angles Theorem

Vertical Angles Theorem
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2016-02-05 11:29
This example illustrates the Vertical Angles Theorem, which states that vertical angles are equal when two lines intersect. Key mathematical concepts include the properties of angles. Using GeoGebra commands such as Point, Rotate, Angle, etc., the nature of vertical angles is demonstrated visually. Suitable for middle school and above students to learn geometric construction.

GeoGebra Commands & Parameters

  1. Point(a) → B
  2. Rotate(B, α, A) → B'
  3. Angle(B, A, B') → β
  4. Line(A, B') → b
  5. Circle(A, 1) → e
  6. Intersect(b, d) → C
  7. Circle(C, 1) → f
  8. Intersect(e, a) → D, E
  9. Intersect(e, b) → F, G
  10. Intersect(f, b) → H, I
  11. Intersect(f, d) → J, K
  12. CircleSector(C, K, I) → g
  13. CircleSector(C, I, J) → h
  14. CircleSector(A, D, F) → s
  15. CircleSector(A, F, E) → t
  16. Dilate(A, If[0 < i < 1, 1 - i], C) → A'
  17. Vector(A, A') → u
  18. Translate(s, u) → s'
  19. Translate(t, u) → t'
  20. CircleArc(C, K, I) → d_1
  21. CircleArc(C, I, J) → e_1
  22. CircleArc(A, D, F) → g_1
  23. CircleArc(A, F, E) → k_1
  24. Rotate(s', ((i * 180))°, A') → s''
  25. Rotate(t', ((i * 180))°, A') → t''