Special Property of Equilateral Triangle

Special Property of Equilateral Triangle
Loading the math board and drawing, please wait…
2016-07-25 10:54
This example demonstrates the special properties of an equilateral triangle. Key mathematical concepts include the properties of equilateral triangles, centroid, orthogonal lines, circles, and angles. Using GeoGebra commands such as Polygon, Segment, Centroid, OrthogonalLine, Circle, and Angle, the construction of an equilateral triangle and exploration of its properties are illustrated. Suitable for middle school and above students to learn geometric construction and related concepts of equilateral triangles.

GeoGebra Commands & Parameters

  1. Polygon(A, B, 3) → poly1, f, g, h, C
  2. Segment(A, B) → i
  3. Segment(B, C) → j
  4. Segment(C, A) → k
  5. Centroid(poly1) → D
  6. OrthogonalLine(D, g) → l
  7. OrthogonalLine(D, i) → m
  8. Intersect(l, g) → E
  9. Circle(D, E) → c
  10. Angle(B, A, C) → α
  11. Rotate(B, 30°, A) → B'
  12. Angle(B, A, B') → β
  13. Line(A, B') → n
  14. Intersect(c, n, 1) → F
  15. Midpoint(A, F) → G
  16. Tangent(F, c) → p,
  17. Intersect(p, i) → H
  18. Intersect(p, h) → I
  19. Polygon(A, H, I) → poly2, i_1, a, h_1
  20. Centroid(poly2) → J
  21. Circle(J, F) → d
  22. Intersect(c, m, 2) → K
  23. Tangent(K, c) → q,
  24. Intersect(q, g) → L
  25. Intersect(q, h) → M
  26. Polygon(M, L, C) → poly3, c_1, m_1, l_1
  27. Centroid(poly3) → N
  28. Circle(N, K) → e
  29. Line(B, D) → r
  30. Intersect(h, k) → O
  31. Intersect(r, h) → P
  32. Intersect(c, r) → Q, R
  33. Tangent(Q, c) → s,
  34. Intersect(s, g) → S
  35. Intersect(s, i) → T
  36. Polygon(T, B, S) → poly4, s_1, t, b
  37. Centroid(poly4) → U
  38. Circle(U, Q) → d_1
  39. Point(cc) → V
  40. Tangent(V, ee) → f_1, g_1
  41. Tangent(V, dd) → j_1, k_1
  42. Tangent(V, ddd) → n_1, p_1
  43. Intersect(e, ee, 1) → W
  44. Intersect(e, ee) → Z, , ,
  45. Intersect(ee, g_1) → A_1
  46. Intersect(dd, j_1) → B_1
  47. Intersect(ddd, n_1) → C_1
  48. Segment(V, A_1) → q_1
  49. Segment(V, B_1) → r_1
  50. Segment(V, C_1) → t_1
  51. Dilate(A, If[0 < o ≤ 1, 1 - o, 0], B) → A'
  52. Segment(A, A') → a_1
  53. Rotate(A, If[1 < o ≤ 2, ((o - 1) * π / 3), π / 3], A) → A'_1
  54. Rotate(A', If[1 < o ≤ 2, ((o - 1) * π / 3), π / 3], A) → A''
  55. Segment(A'_1, A'') → b_1
  56. Rotate(A, If[2 < o ≤ 3, ((-(o - 2)) * π / 3), ((-π)) / 3], B) → A'_2
  57. Rotate(A', If[2 < o ≤ 3, ((-(o - 2)) * π / 3), ((-π)) / 3], B) → A''_1
  58. Segment(A'_2, A''_1) → e_1
  59. Max(list1) → u
  60. Dilate(V, If[4 < o ≤ 5, 5 - o, 0], A_1) → V'
  61. Dilate(V, If[4 < o ≤ 5, 5 - o, 0], C_1) → V'_2
  62. Circle(V, q_1) → c_2
  63. Intersect(c_2, c, 1) → D_1
  64. Intersect(c_2, c) → E_1, F_1, ,
  65. Intersect(c_2, r_1) → G_1,
  66. Dilate(V, If[4 < o ≤ 5, 5 - o, 0], G_1) → V'_1
  67. Dilate(G_1, If[5 < o ≤ 6, 6 - o, 0], B_1) → H_1
  68. Segment(V, V') → f_2
  69. Segment(V, V'_1) → g_2
  70. Segment(V, V'_2) → h_2
  71. Segment(G_1, H_1) → i_2
  72. Angle(A_1, V, B_1) → γ
  73. Rotate(V, If[6 < o ≤ 7, ((o - 6) * γ), γ], V) → V'_3
  74. Rotate(V', If[6 < o ≤ 7, ((o - 6) * γ), γ], V) → V''
  75. Segment(V'_3, V'') → j_2
  76. Dilate(V, If[7 < o ≤ 8, 8 - o, 0], G_1) → V'_4
  77. Vector(V, V'_4) → v
  78. Translate(V, v) → V'_5
  79. Translate(V'_2, v) → I_1
  80. Segment(V'_5, I_1) → k_2
  81. Angle(B_1, V, C_1) → δ
  82. Rotate(V'_5, If[8 < o ≤ 9, ((-(o - 8)) * δ), (-δ)], V'') → J_1
  83. Rotate(I_1, If[8 < o ≤ 9, ((-(o - 8)) * δ), (-δ)], V'') → K_1
  84. Segment(J_1, K_1) → l_2
  85. Circle(V, r_1) → d_2
  86. Intersect(d_2, t_1) → L_1,
  87. Segment(V, V') → m_2
  88. Dilate(V, If[4 < o ≤ 5, 5 - o, 0], B_1) → V'_6
  89. Segment(V, V'_6) → n_2
  90. Dilate(V, If[4 < o ≤ 5, 5 - o, 0], L_1) → V'_7
  91. Segment(V, V'_7) → p_2
  92. Dilate(L_1, If[5 < o ≤ 6, 6 - o, 0], C_1) → M_1
  93. Segment(L_1, M_1) → q_2
  94. Angle(B_1, V, L_1) → ε
  95. Rotate(V, If[6 < o ≤ 7, ((o - 6) * ε), ε], V) → V'_8
  96. Rotate(V'_6, If[6 < o ≤ 7, ((o - 6) * ε), ε], V) → N_1
  97. Segment(V'_8, N_1) → r_2
  98. Dilate(V, If[7 < o ≤ 8, 8 - o, 0], N_1) → V'_9
  99. Vector(V, V'_9) → w
  100. Translate(V, w) → V'_{10}
  101. Translate(V', w) → V''_1
  102. Segment(V'_{10}, V''_1) → s_2
  103. Angle(N_1, V, A_1) → ζ
  104. Rotate(V'_{10}, If[8 < o ≤ 9, ((-(o - 8)) * ζ), (-ζ)], N_1) → O_1
  105. Rotate(V''_1, If[8 < o ≤ 9, ((-(o - 8)) * ζ), (-ζ)], N_1) → P_1
  106. Segment(O_1, P_1) → t_2
  107. Circle(V, t_1) → e_2
  108. Intersect(e_2, q_1) → Q_1,
  109. Dilate(V, If[4 < o ≤ 5, 5 - o, 0], Q_1) → V'_{11}
  110. Dilate(V, If[4 < o ≤ 5, 5 - o, 0], B_1) → V'_{12}
  111. Dilate(V, If[4 < o ≤ 5, 5 - o, 0], C_1) → V'_{13}
  112. Segment(V, V'_{11}) → a_2
  113. Segment(V, V'_{12}) → b_2
  114. Segment(V, V'_{13}) → f_3
  115. Dilate(Q_1, If[5 < o ≤ 6, 6 - o, 0], A_1) → R_1
  116. Segment(Q_1, R_1) → g_3
  117. Angle(C_1, V, Q_1) → η
  118. Rotate(V, If[6 < o ≤ 7, ((o - 6) * η), η], V) → V'_{14}
  119. Rotate(V'_{13}, If[6 < o ≤ 7, ((o - 6) * η), η], V) → S_1
  120. Segment(V'_{14}, S_1) → h_3
  121. Dilate(V, If[7 < o ≤ 8, 8 - o, 0], S_1) → V'_{15}
  122. Vector(V, V'_{15}) → u_1
  123. Translate(V, u_1) → V'_{16}
  124. Translate(V'_{12}, u_1) → T_1
  125. Segment(V'_{16}, T_1) → i_3
  126. Angle(A_1, V, B_1) → θ
  127. Rotate(V'_{16}, If[8 < o ≤ 9, ((-(o - 8)) * θ), (-θ)], S_1) → U_1
  128. Rotate(T_1, If[8 < o ≤ 9, ((-(o - 8)) * θ), (-θ)], S_1) → V_1
  129. Segment(U_1, V_1) → j_3

AI Drawing Prompt Reference

Draw an equilateral triangle, mark its centroid, and draw perpendicular lines from the centroid to each side. Create a circle centered at the centroid passing through the triangle's vertices. Measure the interior angles of the triangle, rotate one vertex by 30 degrees, and connect the original vertex to the rotated vertex. Find intersection points between the perpendicular lines and the circle, and connect these points to form new polygons. Continue this process by drawing circles at these intersection points, finding new intersections, and adding tangent lines to create nested polygons and circles.
The prompt above was compiled from the original drawing commands and is for reference only.