等边三角形的边界与面积关系

GeoGebra 命令及参数

1. Point(xAxis) → J
2. Ray(O, J) → i
3. Point(i) → B
4. Mirror(B, O) → A
5. Polygon(A, B, n) → poly1, a1, b1, b3, C
6. Segment(A, B) → a
7. Ellipse(A, B, a) → k
8. Point(k) → D
9. Polygon(A, D, B) → poly2, b2, a2, c2
10. Ellipse((((-a)) / 2, 0), (a / 2, 0), a) → d
11. Midpoint(A, B) → E
12. Angle(B, E, D) → α
13. Rotate(F, α, O) → F'
14. Line(O, F') → e
15. Intersect(d, e, 2) → G
16. OrthogonalLine(G, xAxis) → g
17. Intersect(f, g, (-2.522724925337565, 5.376576685330704)) → H
18. Segment(H, I) → h