Euclid's Extreme and Mean Proportion Construction

Euclid's Extreme and Mean Proportion Construction
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2018-04-18 04:32
This example demonstrates Euclid's problem of extreme and mean proportion from his Elements. Key mathematical concepts include proportion, similar triangles, and geometric construction. It uses commands like Circle, Line, Point, Intersect, Segment, Polygon, etc. Suitable for middle school and above students to learn about geometric construction and proportion.

GeoGebra Commands & Parameters

  1. Circle(A_1, A_2) → c_1
  2. Line(A_1, C_1) → a_1
  3. Point(c_1) → D
  4. OrthogonalLine(D, a_1) → b_1
  5. Intersect(c_1, a_1, 1) → A
  6. Intersect(a_1, b_1) → C
  7. Segment(A, C) → a
  8. Segment(D, C) → b
  9. Intersect(c_1, a_1, 2) → B
  10. Segment(C, B) → c
  11. Polygon(B, A, 4) → poly1, e, f, g, h, H_1, G
  12. Midpoint(A, H_1) → E
  13. Segment(E, B) → i
  14. Circle(E, B) → k
  15. OrthogonalLine(A, a) → j
  16. Intersect(k, j, 2) → F
  17. Polygon(F, A, 4) → poly2, l, m, n, p, M, H
  18. Segment(D, B) → q
  19. Segment(D, A) → r
  20. Segment(A, B) → s
  21. Segment(A, M) → t
  22. Distance(A, B) → AB
  23. Distance(A, M) → AM
  24. Segment(C, A) → d
  25. Circle(A_{3}, A_{4}) → c_{2}
  26. Line(A_{3}, C_{2}) → a_{2}
  27. Point(c_{2}) → D_{1}
  28. OrthogonalLine(D_{1}, a_{2}) → b_{2}
  29. Intersect(c_{2}, a_{2}, 1) → A_{5}
  30. Intersect(a_{2}, b_{2}) → C_{3}
  31. Segment(A_{5}, C_{3}) → a_{3}
  32. Segment(D_{1}, C_{3}) → b_{3}
  33. Intersect(c_{2}, a_{2}, 2) → B_{1}
  34. Segment(C_{3}, B_{1}) → c_{3}
  35. Polygon(B_{1}, A_{5}, 4) → poly1_{1}, e_{1}, f_{1}, g_{1}, h_{1}, H_{2}, G_{1}
  36. Midpoint(A_{5}, H_{2}) → E_{1}
  37. Segment(E_{1}, B_{1}) → i_{1}
  38. Circle(E_{1}, B_{1}) → k_{1}
  39. OrthogonalLine(A_{5}, a_{3}) → j_{1}
  40. Intersect(k_{1}, j_{1}, 2) → F_{1}
  41. Polygon(F_{1}, A_{5}, 4) → poly2_{1}, l_{1}, m_{1}, n_{1}, p_{1}, M_{1}, H_{3}
  42. Segment(D_{1}, B_{1}) → q_{1}
  43. Segment(D_{1}, A_{5}) → r_{1}
  44. Segment(A_{5}, B_{1}) → s_{1}
  45. Segment(A_{5}, M_{1}) → t_{1}
  46. Distance(A_{5}, B_{1}) → AB_{1}
  47. Distance(A_{5}, M_{1}) → AM_{1}
  48. Segment(C_{3}, A_{5}) → d_{1}

AI Drawing Prompt Reference

Draw a geometric figure demonstrating Euclid's proportion problem. Start by drawing a circle and a line, then find their intersections and draw a perpendicular line. Connect the new intersection points to form two similar quadrilaterals. Next, find midpoints, draw segments, and create circles to locate new intersections, forming similar quadrilaterals again. Finally, connect key points to create multiple segments and quadrilaterals, highlighting the proportion relationships.
The prompt above was compiled from the original drawing commands and is for reference only.