Trapezium Area Demonstration by Mark Dabbs

Trapezium Area Demonstration by Mark Dabbs
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2015-06-19 00:22
This example demonstrates the calculation of the area of a trapezium, involving geometric construction, area formulas, and transformations. It uses GeoGebra commands such as OrthogonalLine, Point, Line, Segment, Midpoint, Polygon, Rotate, Intersect, and If. The construction involves rotating and intersecting objects to visualize the trapezium. Suitable for middle or high school mathematics education to understand the derivation and application of the trapezium area formula.

GeoGebra Commands & Parameters

  1. OrthogonalLine(A, a) → b
  2. Point(b) → B
  3. Line(C, b) → c
  4. Point(c) → D
  5. Segment(C, A) → d
  6. Segment(B, D) → f
  7. Segment(A, B) → g
  8. Segment(C, D) → h
  9. Midpoint(f) → E
  10. Polygon(A, B, D, C) → poly1, a_1, b_1, d_1, c_1
  11. Rotate(A, Rotate, E) → A'
  12. Rotate(B, Rotate, E) → B'
  13. Rotate(D, Rotate, E) → D'
  14. Rotate(C, Rotate, E) → C'
  15. Polygon(A', B', D', C') → poly1', a', b', d', c'
  16. Midpoint(C, A) → F
  17. Midpoint(B, D) → G
  18. OrthogonalLine(F, h) → j
  19. OrthogonalLine(G, h) → k
  20. Intersect(k, h) → H
  21. Intersect(j, h) → I
  22. Intersect(k, g) → J
  23. Intersect(j, g) → K
  24. Line(C, D) → l
  25. Line(A, B) → m
  26. Intersect(j, l) → L
  27. Intersect(k, m) → M
  28. Intersect(j, m) → N
  29. Intersect(k, l) → O
  30. Point(k) → P
  31. Polygon(P, O, D) → poly2, d_2, p, o
  32. Point(j) → Q
  33. Polygon(N, Q, A) → poly3, a_2, n, q
  34. Polygon(B, P, M) → poly4, m_1, b_2, p_1
  35. Polygon(Q, L, C) → poly5, c_2, q_1, l_1
  36. Rotate(P, α, G) → P'
  37. Rotate(O, α, G) → O'
  38. Rotate(D, α, G) → D'_1
  39. Polygon(P', O', D'_1) → poly2', d'_1, p', o'
  40. Rotate(N, α, F) → N'
  41. Rotate(Q, α, F) → Q'
  42. Rotate(A, α, F) → A'_1
  43. Polygon(N', Q', A'_1) → poly3', a'_1, n', q'
  44. Rotate(B, (-α), G) → B'_1
  45. Rotate(P, (-α), G) → P'_1
  46. Rotate(M, (-α), G) → M'
  47. Polygon(B'_1, P'_1, M') → poly4', m', b'_1, p'_1
  48. Rotate(Q, (-α), F) → Q'_1
  49. Rotate(L, (-α), F) → L'
  50. Rotate(C, (-α), F) → C'_1
  51. Polygon(Q'_1, L', C'_1) → poly5', c'_1, q'_1, l'
  52. If(x(A) > x(C), If[x(B) < x(D), Polygon[A, B, G, O, L, F], Polygon[A, M, G, D, L, F]], If[x(B) < x(D), Polygon[N, B, G, O, C, F], Polygon[N, M, G, D, C, F]]) → polyHex
  53. If(x(A) > x(C), If[x(B) < x(D), Polygon[A, B, G, O, L, F], Polygon[A, M, G, D, L, F]], If[x(B) < x(D), Polygon[N, B, G, O, C, F], Polygon[N, M, G, D, C, F]]) → polyHexBorder
  54. Midpoint(B, D) → R
  55. Line(A, R) → s
  56. Line(C, D) → t
  57. Intersect(t, s) → S
  58. Polygon(A, B, R) → poly6, r_1, a_3, b_3
  59. Rotate(A, (-β), R) → A'_2
  60. Rotate(B, (-β), R) → B'_2
  61. Rotate(R, (-β), R) → R'
  62. Polygon(A'_2, B'_2, R') → poly6', r', a'_2, b'_2
  63. Polygon(A, C, D, R) → poly7, a_4, c_3, d_3, r_2
  64. Polygon(A, R, D, C) → poly8, a_5, r_3, d_4, c_4
  65. Polygon(A'_2, B'_2, R) → poly9, r_4, a'_3, b'_3
  66. Segment(F, G) → e_1
  67. Polygon(F, G, B, A) → poly10, f_1, g_1, b_4, a_6
  68. Rotate(F, (-γ), G) → F'
  69. Rotate(G, (-γ), G) → G'
  70. Rotate(B, (-γ), G) → B'_3
  71. Rotate(A, (-γ), G) → A'_3
  72. Polygon(F', G', B'_3, A'_3) → poly10', f', g', b'_4, a'_4
  73. Polygon(C, F, G, D) → poly11, c_5, f_2, g_2, d_5
  74. Midpoint(Bt, Dt) → T
  75. Polygon(A, D, B) → poly12, b_5, a_7, d_6
  76. Rotate(A, (-δ), T) → A'_4
  77. Rotate(D, (-δ), T) → D'_2
  78. Rotate(B, (-δ), T) → B'_4
  79. Polygon(A'_4, D'_2, B'_4) → poly12', b'_5, a'_5, d'_2
  80. Segment(A, D) → h_1
  81. Segment(A, D) → i_1
  82. Polygon(A, C, D) → poly13, d_7, a_8, c_6
  83. Segment(Ah, Dh) → j_1
  84. OrthogonalLine(Ah, c) → k_1
  85. OrthogonalLine(Dh, c) → n_1
  86. Point(k_1) → V
  87. Point(n_1) → W
  88. OrthogonalLine(V, c) → t_1
  89. OrthogonalLine(W, c) → e_2
  90. Intersect(t_1, c) → Z
  91. Intersect(e_2, c) → A_1
  92. Segment(A_1, Z) → s_1

AI Drawing Prompt Reference

Draw a trapezium shape with four vertices A, B, C, and D. Construct perpendicular lines, points, line segments, and midpoints. Then rotate points A, B, C, and D to new positions to form new polygons like poly1'. Construct perpendicular lines and intersect them with original segments to get points H, I, J, K. Use intersection operations to create more polygons such as poly2, poly3, poly4, and poly5. Further rotate points P, O, D to form poly2', and points N, Q, A to form poly3'. Finally, complete the trapezium area verification by combining rotations and intersections.
The prompt above was compiled from the original drawing commands and is for reference only.