Quadrilateral Interior & Exterior Angle Sum Theorems (V2)

Quadrilateral Interior & Exterior Angle Sum Theorems (V2)
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2015-10-23 09:01
① This applet dynamically demonstrates that the sum of interior angles of any quadrilateral is always 360°, and that the sum of its exterior angles is also 360°. ② Core mathematical concepts: quadrilaterals, interior angles, exterior angles, angle sum theorems, polygon angle properties. ③ Construction highlights: the model is built with GeoGebra commands Ray, Point, Circle, Intersect, Segment, Angle, CircleSector, Vector, Translate, Dilate, If, Line, Polygon, Rotate, Mirror to create vertices, edges, rays, arcs, sectors, vectors, translations, dilations, conditional logic, rotations, and reflections, enabling interactive angle measurement and summation. ④ Suitable for middle‑school geometry (grades 7‑9) lessons on angles and polygons, for classroom demonstration, student exploration, and exam review.

GeoGebra Commands & Parameters

  1. Ray(P, A) → h_1
  2. Point(h_1) → R
  3. Ray(A, R) → j_1
  4. Ray(A, B) → a
  5. Circle(A, 1.5) → g
  6. Intersect(g, j_1) → I_1,
  7. Intersect(g, a, 1) → H
  8. Segment(P, A) → l_1
  9. Intersect(g, l_1, 1) → H_1
  10. Segment(P, C) → k_1
  11. Circle(C, 1.5) → k
  12. Intersect(k, k_1) → Z,
  13. Ray(B, C) → b
  14. Intersect(k, b) → M, N
  15. Point(a) → D_1
  16. Point(b) → E_1
  17. Ray(B, D_1) → e
  18. Ray(C, E_1) → f
  19. Point(e) → D
  20. Point(f) → E
  21. Angle(A, C, B) → γ
  22. Angle(D, B, C) → ε
  23. Angle(E, C, A) → ζ
  24. Circle(B, 1.5) → h
  25. Intersect(h, b, 1) → J
  26. Intersect(h, a, 1) → K
  27. Intersect(h, a, 2) → L
  28. CircleSector(B, J, K) → q
  29. CircleSector(B, L, J) → t
  30. Vector(B, C) → u
  31. CircleSector(A, I_1, H) → c_1
  32. Vector(A, C) → v
  33. Translate(q, u) → q'
  34. Segment(B, C) → l
  35. Dilate(C, If[0 < j ≤ 1, j, 0], B) → C'
  36. Vector(B, C') → w
  37. Translate(q, w) → q'_1
  38. Dilate(A, If[1 < j ≤ 2, 2 - j, 0], C) → C'_1
  39. Vector(A, C'_1) → m
  40. Dilate(C, If[0 < n ≤ 1, n, 0], B) → C'_2
  41. Dilate(A, If[1 < n ≤ 2, 2 - n, 0], C) → A'
  42. Vector(B, C'_2) → u_1
  43. Vector(A, A') → v_1
  44. If(0 < n ≤ 1, Translate[t, u_1], Translate[t, u]) → e_1
  45. If(1 < n ≤ 2, Translate[c_1, v_1], Translate[c_1, v]) → f_1
  46. Ray(C, P) → g_1
  47. Point(g_1) → Q
  48. Ray(P, Q) → i_1
  49. Point(i_1) → S
  50. Point(j_1) → T
  51. Circle(P, 1.5) → p_1
  52. Intersect(p_1, l_1) → U,
  53. Intersect(p_1, i_1) → V,
  54. Intersect(p_1, k_1) → W,
  55. CircleSector(P, U, W) → q_1
  56. Intersect(k, b, 2) → A_1
  57. Line(P, b) → b_1
  58. Intersect(p_1, b_1) → C_1, G_1
  59. Angle(B, A, P) → α
  60. Vector(P, C) → i
  61. Dilate(P, If[2 < j ≤ 3, 3 - j, 0], C) → P'
  62. Vector(P, P') → w_1
  63. Translate(q_1, w_1) → r_1
  64. CircleSector(C, N, Z) → s
  65. CircleSector(P, V, U) → t_1
  66. Dilate(P, If[2 < n ≤ 3, 3 - n, 0], C) → P'_1
  67. Vector(P, P'_1) → m_1
  68. If(2 < n ≤ 3, Translate[t_1, m_1], Translate[t_1, w_1]) → e_2
  69. Angle(H, A, I_1) → δ
  70. Angle(V, P, U) → η
  71. Angle(U, P, W) → θ
  72. Polygon(A, B, C, P) → poly1, a_2, b_2, c_2, p_2
  73. Segment(A, C) → n_1
  74. Intersect(g, n_1) → F,
  75. Intersect(k, n_1) → G,
  76. Line(P, n_1) → c
  77. Line(B, n_1) → d
  78. CircleSector(C, Z, G) → d_1
  79. CircleSector(C, G, M) → s_1
  80. CircleSector(A, H, F) → d_2
  81. If(0 < j ≤ 1, Dilate[C, 1 - j, B]) → I
  82. If(1 < j ≤ 2, Dilate[A, 2 - j, P]) → O
  83. If(1 < j ≤ 2, Dilate[C, 2 - j, P]) → B_1
  84. Vector(C, I) → r
  85. Vector(A, O) → u_2
  86. Translate(s_1, r) → h_2
  87. Dilate(A, If[0 < j ≤ 1, 1 - j, Distance[A, B]], B) → A'_1
  88. Vector(A, A'_1) → p
  89. Translate(d_2, p) → g_2
  90. Rotate(d_2, 180*°, A) → k_2
  91. Vector(A, B) → v_2
  92. Translate(k_2, v_2) → q_2
  93. Rotate(g_2, ((j * 180))°, A'_1) → r_2
  94. Vector(C, B) → w_2
  95. Translate(s_1, w_2) → s_2
  96. Mirror(s_2, B) → t_2
  97. Rotate(h_2, ((j * 180))°, I) → c_3
  98. Vector(A, P) → i_2
  99. Vector(C, P) → j_2
  100. CircleSector(A, F, H_1) → f_2
  101. Translate(f_2, i_2) → d_3
  102. Mirror(d_3, P) → e_3
  103. Vector(C, B_1) → l_2
  104. Translate(d_1, j_2) → f_3
  105. Mirror(f_3, P) → g_3
  106. Translate(f_2, u_2) → h_3
  107. Translate(d_1, l_2) → k_3
  108. Rotate(h_3, (((j - 1) * 180))°, O) → p_3
  109. Rotate(k_3, (((j - 1) * 180))°, B_1) → q_3
  110. Segment(A, B) → m_2
  111. Polygon(A, B, C) → poly2, c_4, a_3, b_3
  112. Polygon(A, C, P) → poly3, p_4, a_4, c_5

AI Drawing Prompt Reference

Draw a quadrilateral with points A, B, C, D, and E and their connecting segments. Start by drawing point A and point B, then draw a ray from A that intersects a circle to get point C. Next, draw a ray from B to C that intersects the circle to get point D. Draw another ray from C to D that intersects the circle to get point E. Finally, connect points A, B, C, D, and E to form the quadrilateral and measure its interior and exterior angles to ensure the interior angles sum to 360 degrees and the exterior angles also sum to 360 degrees.
The prompt above was compiled from the original drawing commands and is for reference only.