Dynamic Illustration of Compass-and-Straightedge Trisection by Tim Brzezinski

Dynamic Illustration of Compass-and-Straightedge Trisection by Tim Brzezinski
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2018-05-18 23:11
This example dynamically illustrates a compass-and-straightedge method for trisecting a line segment. It involves core mathematical concepts such as geometric construction, circles, angles, and similar triangles. The construction utilizes commands and objects like Mirror, Segment, Dilate, Circle, Rotate, Intersect, Angle, CircleArc, Distance, and Midpoint from GeoGebra. It is suitable for high school mathematics education or for enthusiasts learning complex geometric construction techniques.

GeoGebra Commands & Parameters

  1. Mirror(B, A) → B'_5
  2. Segment(A, B) → f
  3. Dilate(A, If[0 < a ≤ 1, 1 - a, 0], B) → A'
  4. Dilate(B, If[1 < a ≤ 2, 2 - a, 0], B'_5) → B'
  5. Circle(A, A') → c
  6. Rotate(A, If[5.5 < a ≤ 6.5, ((a - 5.5) * π / 3), π / 3], A) → A'_1
  7. Rotate(B, If[5.5 < a ≤ 6.5, ((a - 5.5) * π / 3), π / 3], A) → B'_3
  8. Rotate(A, If[5.5 < a ≤ 7.5, ((-(a - 6.5)) * π / 3), ((-π)) / 3], B) → A'_2
  9. Rotate(B, If[5.5 < a ≤ 7.5, ((-(a - 6.5)) * π / 3), ((-π)) / 3], B) → B'_4
  10. Mirror(B'_5, B) → C
  11. Dilate(B, If[2 < a ≤ 3, 3 - a, 0], C) → B'_1
  12. Segment(B, B'_1) → g
  13. Circle(C, A) → d
  14. Intersect(c_1, d, 1) → D
  15. Segment(A, C) → h
  16. Angle(D, C, A) → β
  17. Rotate(A, If[3 < a ≤ 4, ((-(a - 3)) * β), (-β)], C) → A'_3
  18. Rotate(C, If[3 < a ≤ 4, ((-(a - 3)) * β), (-β)], C) → C'
  19. Segment(A'_3, C') → h'
  20. CircleArc(C, A'_3, A) → e
  21. Circle(D, A) → k
  22. Intersect(k, f) → E, F
  23. Dilate(D, If[5 < a ≤ 6, 6 - a, 0], A) → D'
  24. Circle(D, D') → p
  25. Distance(F, A) → b
  26. Midpoint(F, B) → G
  27. Dilate(A, If[7 < a ≤ 8, 8 - a, 0], F) → A'_4
  28. Segment(A, A'_4) → j
  29. Dilate(F, If[8 < a ≤ 9, 9 - a, 0], G) → F'
  30. Dilate(G, If[9 < a ≤ 10, 10 - a, 0], B) → G'
  31. Segment(F, F') → l
  32. Segment(G, G') → m
  33. Rotate(A, If[10.5 < a ≤ 11.5, ((a - 10.5) * π), π], F) → A'_5
  34. Rotate(A'_4, If[10.5 < a ≤ 11.5, ((a - 10.5) * π), π], F) → H
  35. Segment(A'_5, H) → j'
  36. Rotate(A'_5, If[11.5 < a ≤ 12.5, ((a - 11.5) * π), π], G) → I
  37. Rotate(H, If[11.5 < a ≤ 12.5, ((a - 11.5) * π), π], G) → H'
  38. Segment(I, H') → j''

AI Drawing Prompt Reference

Draw a line segment AB and trisect it using circles and angles. First, construct auxiliary circles and segments by mirroring and scaling. Then, use rotation and intersection to find the trisection points. Finally, complete the trisection through a series of rotations and reflections.
The prompt above was compiled from the original drawing commands and is for reference only.