Volume of Spheres Copy (no proof window)

Volume of Spheres Copy (no proof window)
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2019-05-21 09:12
① This GeoGebra example demonstrates the volume of a sphere in relation to cylinders and cones through an interactive 3D visualization, allowing learners to intuitively grasp the derivation of the sphere volume formula. ② Core mathematical concepts include sphere volume, cylinder volume, cone volume, inscribed circles, polygonal approximation, solids of revolution, and volume optimization ideas from linear programming. ③ Construction highlights: using GeoGebra commands such as Circle, Point, Sphere, Cylinder, Cone, Segment, OrthogonalPlane, IntersectPath, Intersect, Rotate, Polygon, Sequence, Angle, and Surface, the model builds a sphere, cylinder, cone, and auxiliary cross-sections, with rotation and intersection paths to create multiple solids for dynamic exploration. ④ Suitable for upper secondary or early university students studying solid geometry and volume formulas, and useful for teachers as a classroom demonstration tool, especially for exploring the proportional relationships among sphere, cylinder, and cone volumes.

GeoGebra Commands & Parameters

  1. Circle(A, 1) → c
  2. Circle(B, 1) → d
  3. Point(c) → C
  4. Sphere(A, C) → a
  5. Cylinder(B, D, 1) → b, e, f, g
  6. Cone(D, B, 1) → h, k, i
  7. Segment(E, E + (0, 0, 1)) → j
  8. Point(j) → F
  9. OrthogonalPlane(F, j) → l
  10. IntersectPath(l, a) → p
  11. IntersectPath(l, h) → q
  12. IntersectPath(l, b) → r
  13. Point(q) → H
  14. Intersect(Ray[G, H], r) → I,
  15. Rotate(H, α, G) → H'
  16. Rotate(I, α, G) → I'
  17. Polygon(H, H', I', I) → poly1, h_1, h', i', i_1
  18. Sequence(Rotate[poly1, (k * α), G], k, 0, n) → list1
  19. Intersect(Ray[J, J + (1, 0, 0)], p) → K,
  20. Segment(A, J) → s
  21. Segment(J, K) → t
  22. Segment(K, A) → a_1
  23. Intersect(Ray[G, G + (1, 0, 0)], q) → L, M
  24. Segment(B, G) → b_1
  25. Segment(G, L) → c_1
  26. Circle(s, C) → d_1
  27. Angle(A, J, K) → β
  28. Angle(B, G, L) → γ
  29. Circle(B, 1, Segment[B, B + (0, 0, 1)]) → e_1
  30. Surface((sqrt(1 - h^(2)) * cos(θ)) + x(A), (sqrt(1 - h^(2)) * sin(θ)) + y(A), h, θ, 0, 6.28319, h, 0, 1) → o