Point of Concurrency of Angle Bisectors - Incenter by John Sweeney

Point of Concurrency of Angle Bisectors - Incenter by John Sweeney
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2015-11-26 06:49
This example demonstrates that the angle bisectors of a triangle are concurrent at the incenter. It involves core concepts like angle bisectors, incenter of a triangle, and geometric construction. Key GeoGebra commands used include Polygon, AngularBisector, Intersect, Angle, OrthogonalLine, Segment, and Circle. Suitable for middle school students and above to learn about triangle properties and geometric constructions.

GeoGebra Commands & Parameters

  1. Polygon(A, B, C) → poly1, c, a, b
  2. AngularBisector(A, C, B) → d
  3. AngularBisector(B, A, C) → e
  4. AngularBisector(A, B, C) → f
  5. Intersect(e, d) → I
  6. Angle(B, A, C) → α
  7. Angle(A, B, C) → β
  8. Angle(A, C, B) → γ
  9. OrthogonalLine(I, c) → g
  10. Intersect(c, g) → D
  11. OrthogonalLine(I, b) → h
  12. Intersect(b, h) → E
  13. OrthogonalLine(I, a) → i
  14. Intersect(i, a) → F
  15. Segment(I, E) → j
  16. Segment(I, F) → k
  17. Segment(I, D) → l
  18. Circle(I, E) → p
  19. Angle(A, E, I) → δ
  20. Angle(I, F, B) → ε
  21. Angle(I, D, B) → ζ

AI Drawing Prompt Reference

Draw a triangle and its three angle bisectors to show they concur at the incenter. Then, draw perpendiculars from the incenter to the three sides, marking the feet of the perpendiculars. Finally, connect the incenter to these three feet and draw a circle centered at the incenter with a radius equal to the distance to one of the feet.
The prompt above was compiled from the original drawing commands and is for reference only.