Truncated Icosahedron: Average Vertex Distance vs Truncation Parameter and Extre

Truncated Icosahedron: Average Vertex Distance vs Truncation Parameter and Extre
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2020-01-11 23:56
①This example demonstrates how the average distance between vertices of a truncated icosahedron (an Archimedean solid) changes with the truncation parameter, and shows the extreme distribution of this average. ②Core mathematical concepts include solid geometry of polyhedron truncation, statistical averaging of inter-vertex distances, optimization problems, and function graphs with parameter-dependent extrema. ③Construction highlights: using GeoGebra commands such as Join, Unique, Length, Sum, Sphere, Ray, Zip, UnicodeToLetter, and TableText to build vertex sets and distance computations; a slider controls the truncation parameter t, dynamically updating vertex list lP' and distance list lVV, and plotting the average distance function; buttons and text objects display results, involving objects like polyhedron vertices, spheres, rays, and table text. ④Suitable for high school to university mathematics teaching, for exploring solid geometry, optimization, and parametric modeling, as well as for math labs or competition enrichment.

GeoGebra Commands & Parameters

  1. Join(Zip[lP0(x(a)) + ((lP0(y(a)) - lP0(x(a))) * {t, 1 - t}), a, segN]) → lVV
  2. Unique(lVV) → lP'
  3. Length(lP') → n
  4. Length(lVV(1)) → R2
  5. Text("" + p3) → txt_p
  6. Sum(Flatten[Sequence[Append[Sequence[Element[txt_p, i], i, m1(k), m2(k)], " "], k, 1, 5]]) → txtUm1
  7. Sphere(O, R1) → sp1
  8. Sphere(O, R2) → sp2
  9. Ray(B, AA) → h
  10. Zip(Polygon[a], a, v_poly06) → poly06
  11. Zip(Polygon[a], a, v_poly05) → poly05
  12. Text(text12, C, false, true) → text8
  13. Zip(Segment[lP0(x(a)), lP0(y(a))], a, segN1) → seg1
  14. Zip(Segment[lP0(x(a)), lP0(y(a))], a, segN2) → seg2
  15. UnicodeToLetter(34) → u34
  16. Zip(Segment[lVV(x(a)), lVV(y(a))], a, segNΔ5) → segΔ5
  17. Zip(Segment[lVV(x(a)), lVV(y(a))], a, segNΔ6) → segΔ6
  18. TableText(Append["\;\;\; \fgcolor{#848482}{5-gons}", segΔ5], Append["\;\;\; \fgcolor{#007FFF}{6-gons}", segΔ6], "v") → text3a