菱形面积计算 by Jordan Varney

菱形面积计算 by Jordan Varney
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2018-03-05 03:09
①本范例演示如何通过构造菱形的对角线来计算其面积;②涉及核心数学概念包括菱形性质、对角线垂直平分、勾股定理、三角形面积公式;③作图要点:使用Segment, LineBisector, Point, Intersect, Polygon, Midpoint, Rotate, Angle等GeoGebra命令和对象进行菱形及其对角线的构造与测量;④适合初中及以上学生学习菱形面积计算方法,也可用于几何作图教学。

GeoGebra 命令及参数

  1. Segment(A, B) → f
  2. LineBisector(f) → g
  3. Point(g) → C
  4. Point(g) → D
  5. Intersect(g, f) → E
  6. Polygon(A, E, C) → t1_1, c, a, e
  7. Polygon(C, E, B) → t2_1, b, c_1, e_1
  8. Polygon(A, D, E) → t3_1, e_2, a_1, d
  9. Polygon(D, E, B) → t4_1, b_1, d_1, e_3
  10. Midpoint(e) → F
  11. Midpoint(e_2) → G
  12. Midpoint(e_3) → H
  13. Midpoint(e_1) → I
  14. Rotate(A, t1, F) → A'
  15. Rotate(E, t1, F) → E'
  16. Rotate(C, t1, F) → C'
  17. Polygon(A', E', C') → t5, c', a', e'
  18. Rotate(C, t2, I) → C'_1
  19. Rotate(E, t2, I) → E'_1
  20. Rotate(B, t2, I) → B'
  21. Polygon(C'_1, E'_1, B') → t6, b', c'_1, e'_1
  22. Rotate(D, t3, H) → D'
  23. Rotate(E, t3, H) → E'_2
  24. Rotate(B, t3, H) → B'_1
  25. Polygon(D', E'_2, B'_1) → t7, b'_1, d', e'_2
  26. Rotate(A, t4, G) → A'_1
  27. Rotate(D, t4, G) → D'_1
  28. Rotate(E, t4, G) → E'_3
  29. Polygon(A'_1, D'_1, E'_3) → t8, e'_3, a'_1, d'_1
  30. Angle(C, E, A) → α
  31. Angle(C, E'_1, B) → β