Centers of a Triangle

Centers of a Triangle
Loading the math board and drawing, please wait…
2015-02-07 01:36
This example illustrates the three important centers of a triangle: the centroid, orthocenter, and circumcenter. By constructing the medians, altitudes, and circumcircle of a triangle, one can visually understand these concepts. Commands used include Segment, Midpoint, Intersect, OrthogonalLine, Angle, Rotate, Ray, Line, and Circle. Suitable for middle school and above students learning geometry.

GeoGebra Commands & Parameters

  1. Segment(A, C) → a
  2. Segment(C, B) → b
  3. Segment(A, B) → c
  4. Midpoint(A, C) → D
  5. Midpoint(A, B) → E
  6. Midpoint(C, B) → F
  7. Segment(A, F) → d
  8. Segment(D, B) → e
  9. Segment(E, C) → f
  10. Intersect(d, e) → Centroid
  11. OrthogonalLine(B, a) → g
  12. OrthogonalLine(A, b) → h
  13. OrthogonalLine(C, c) → i
  14. Intersect(g, h) → Orthocenter
  15. OrthogonalLine(F, b) → j
  16. OrthogonalLine(D, a) → k
  17. OrthogonalLine(E, c) → l
  18. Intersect(j, k) → Circumcenter
  19. Angle(C, A, B) → α
  20. Angle(A, B, C) → β
  21. Angle(B, C, A) → γ
  22. Rotate(C, α / 2, A) → C'
  23. Angle(C, A, C') → δ
  24. Ray(A, C') → m
  25. Rotate(B, β / 2, A) → B'
  26. Rotate(B, β / 2, A) → B'_1
  27. Rotate(A, β / 2, B) → A'
  28. Angle(A, B, A') → ε
  29. Ray(B, A') → n
  30. Rotate(B, γ / 2, C) → B'_2
  31. Angle(B, C, B'_2) → ζ
  32. Ray(C, B'_2) → p
  33. Intersect(m, n) → Incenter
  34. Line(Orthocenter, Circumcenter) → Euler
  35. Intersect(i, c) → G
  36. Intersect(h, b) → H
  37. Intersect(g, a) → I
  38. Segment(G, I) → q
  39. Segment(H, I) → r
  40. Segment(H, G) → s
  41. OrthogonalLine(Orthocenter, q) → t
  42. Intersect(t, q) → J
  43. Circle(Orthocenter, J) → c_1
  44. Circle(Circumcenter, C) → d_1
  45. OrthogonalLine(Incenter, c) → a_1
  46. Intersect(a_1, c) → K
  47. Circle(Incenter, K) → e_1

AI Drawing Prompt Reference

Draw a triangle ABC, then construct its three medians, three altitudes, and the circumcircle. Find the centroid, orthocenter, and circumcenter. Next, construct the angle bisectors to find the incenter. Finally, connect the centroid, circumcenter, and incenter to observe the Euler line.
The prompt above was compiled from the original drawing commands and is for reference only.