Unfolding Cones

Unfolding Cones
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2022-11-11 22:50
Explore the geometry of cones by unfolding and folding their nets. Change the dimensions of the cone to see how the net changes and understand its geometry. Key math concepts include surface area and volume of cones. Constructed using GeoGebra commands like Point, Circle, Ray, Sequence, Polygon, OrthogonalLine, Segment, Net, Cone. Suitable for grades 6-8 students learning to identify nets of prisms, pyramids, cylinders, and cones.

GeoGebra Commands & Parameters

  1. Point(yAxis) → CA
  2. Point(yAxis) → CB
  3. Circle(CA, CB) → cCil
  4. Point(cCil) → C
  5. Ray(A, (x(A), y(A), 40)) → h
  6. Point(yAxis) → B
  7. Sequence(Rotate[C, ((t * 2) * pi / n), A], t, 1, n) → vert
  8. Polygon(vert) → poly
  9. OrthogonalLine(C, xOyPlane) → f
  10. Segment(HC, (x(C), y(C), 4)) → g
  11. Point(g) → E
  12. Prism(poly, Segment[C, E]) → a, F, face3, face4, face5, face6, face2, face13, face15, faceFGHIJK, edge1, edge2, G, edge3, edge4, edge5, edge6, edge13, edge16, edgeFG, edgeGH, edgeHI, edgeIJ, H, edgeJK, edgeFK, edge14, edge17, I, J, K, L, M, face1
  13. Point(Segment[(0, 0, 0.1), (0, 0, 4)]) → CD
  14. Pyramid(poly, CD) → b, face7, edge8, edge9, edge10, edge11, edge12, edge15, edge18, face9, face10, face11, face12, face8, face14, face16, edge7
  15. Net(a, (-open)) → prismNet, N, W, Z, A_1, B_1, C_1, D_1, E_1, F_1, G_1, H_1, O, I_1, J_1, K_1, L_1, M_1, N_1, O_1, P_1, Q_1, R_1, P, S_1, face17, face18, face19, face20, face21, face22, face23, face24, face34, Q, face35, edge19, edge20, edge21, edge22, edge23, edge24, edge25, edge26, edge27, R, edge28, edge29, edge30, edge31, edge32, edge33, edge34, edge35, edge36, edge37, S, edge38, edge39, edge40, edge41, edge42, edge43, edge44, edge45, edge70, edge71, T, edge72, edge73, edge74, edge75, edge76, edge77, edge78, edge79, edge80, edge81, U, V
  16. Net(b, (-open)) → pyrNet, T_1, E_2, F_2, G_2, H_2, I_2, J_2, K_2, face25, face26, face27, U_1, face28, face29, face30, face31, face32, face33, edge46, edge47, edge48, edge49, V_1, edge50, edge51, edge52, edge53, edge54, edge55, edge56, edge57, edge58, edge59, W_1, edge60, edge61, edge62, edge63, edge64, edge65, edge66, edge67, edge68, edge69, Z_1, A_2, B_2, C_2, D_2
  17. Random(3, 8) → nRand
  18. Circle(CA, CB) → d
  19. Cylinder(cCil, 3) → bCil, eCil, fCil
  20. Line(CC, xAxis) → aCil
  21. OrthogonalLine(CD, xOyPlane) → gCil
  22. Circle(gCil, CC) → kCil
  23. Rotate(Rotate[eCil, ϕCil, aCil], ϕCil, xAxis) → eeCil
  24. Rotate(Rotate[eCil, ϕCil, aCil], ϕCil, xAxis) → dCil
  25. Circle(CA, CB) → hCil
  26. If(abs(tCil) < 1, ((rCil * sin((-θCil))), ((rCil * (1 - cos((-θCil)))) * cos(ϕCil)) - (3 * sin(ϕCil)), (3 * cos(ϕCil)) + ((rCil * (1 - cos((-θCil)))) * sin(ϕCil))), ((-pi), (-3 * sin(ϕCil)), (3 * cos(ϕCil)))) → CE
  27. If(abs(tCil) < 1, ((rCil * sin(θCil)), ((rCil * (1 - cos(θCil))) * cos(ϕCil)) - (3 * sin(ϕCil)), (3 * cos(ϕCil)) + ((rCil * (1 - cos(θCil))) * sin(ϕCil))), (pi, (-3 * sin(ϕCil)), (3 * cos(ϕCil)))) → CF
  28. If(abs(tCil) < 1, ((rCil * sin((-θCil))), ((rCil * (1 - cos((-θCil)))) * cos(ϕCil)), ((rCil * (1 - cos((-θCil)))) * sin(ϕCil))), ((-pi), 0, 0)) → CG
  29. If(abs(tCil) < 1, ((rCil * sin(θCil)), ((rCil * (1 - cos(θCil))) * cos(ϕCil)), ((rCil * (1 - cos(θCil))) * sin(ϕCil))), (pi, 0, 0)) → CH
  30. Segment(CE, CG) → mCil
  31. Segment(CF, CH) → nCil
  32. Line((0, 1, 0), zAxis) → pCil
  33. Circle(pCil, CB) → qCil
  34. Circle(pCil, CB) → sCil
  35. Segment((1, 0, 0), (1, 0, 5)) → aCon
  36. Circle(aCon, (0, 0, 0)) → cCon
  37. Point(aCon) → KA
  38. Intersect(xAxis, aCon) → KB
  39. Cone(KB, KA, 1) → bCon, dCon, eCon
  40. Intersect(yAxis, xAxis) → KC
  41. Segment(KC, KA) → lCon
  42. Distance(KB, KC) → rCon
  43. Angle(KA, KC, KB) → α
  44. Rotate(KA, (abs(tCil) * α), yAxis) → KAA
  45. OrthogonalLine(KAA, xOyPlane) → fCon
  46. Intersect(fCon, xOyPlane) → KBB
  47. Rotate(KC, bet / 2, fCon) → KCC
  48. Rotate(KC, ((-bet)) / 2, fCon) → KCR
  49. CircumcircleArc(KCC, KC, KCR) → gCon
  50. Distance(KAA, KBB) → hCon
  51. Distance(KBB, KCC) → rcCon
  52. Surface(((kCon - ((v * rcCon) * cos((u * bet / 2)))) * cos(ϕCon)) - (((1 - v) * hCon) * sin(ϕCon)), ((v * rcCon) * sin((u * bet / 2))), (((1 - v) * hCon) * cos(ϕCon)) + ((kCon - ((v * rcCon) * cos((u * bet / 2)))) * sin(ϕCon)), u, -1, 1, v, 0, 1) → jCon
  53. CurveCartesian(((kCon - (rcCon * cos((u * bet / 2)))) * cos(ϕCon)), (rcCon * sin((u * bet / 2))), ((kCon - (rcCon * cos((u * bet / 2)))) * sin(ϕCon)), u, -1, 1) → mCon
  54. Segment(KE, KF) → nCon
  55. Segment(KD, KF) → pCon
  56. If(abs(tCil) < 1, CurveCartesian[(rCil * sin((u * θCil))), ((rCil * (1 - cos((u * θCil)))) * cos(ϕCil)) - (3 * sin(ϕCil)), (3 * cos(ϕCil)) + ((rCil * (1 - cos((u * θCil)))) * sin(ϕCil)), u, -1, 1], CurveCartesian[(pi * u), (-3 * sin(ϕCil)), (3 * cos(ϕCil)), u, -1, 1]) → jCil
  57. If(abs(tCil) < 1, CurveCartesian[(rCil * sin((u * θCil))), ((rCil * (1 - cos((u * θCil)))) * cos(ϕCil)), ((rCil * (1 - cos((u * θCil)))) * sin(ϕCil)), u, -1, 1], CurveCartesian[(pi * u), 0, 0, u, -1, 1]) → lCil
  58. If(abs(tCil) < 1, Surface[(rCil * sin((u * θCil))), ((rCil * (1 - cos((u * θCil)))) * cos(ϕCil)) - (v * sin(ϕCil)), (v * cos(ϕCil)) + ((rCil * (1 - cos((u * θCil)))) * sin(ϕCil)), u, -1, 1, v, 0, 3], Surface[(pi * u), ((-v) * sin(ϕCil)), (v * cos(ϕCil)), u, -1, 1, v, 0, 3]) → iCil

AI Drawing Prompt Reference

Create a 3D cone together with its unfolded net. First define the cone’s base circle in space using a base center and two points on the circle, then determine the cone by connecting the apex to the base circle and setting its height/radius using the chosen construction parameters. Next, split the circular rim into n equal positions and use the corresponding generatrix segments from the apex to unfold the cone’s lateral surface into a flat pattern composed of several connected sector-like polygon faces. Show the essential relations: the base circle, the apex, the generatrix connections that match the unfolded seams, and the resulting net lying in a plane so the folding correspondence is visually clear.
The prompt above was compiled from the original drawing commands and is for reference only.