Elongated pentagonal orthobirotunda

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Elongated pentagonal orthobirotunda
Elongated pentagonal orthobirotunda.png
Type Johnson
J41 - J42 - J43
Faces 2.10 triangles
2.5 squares
2+10 pentagons
Edges 80
Vertices 40
Vertex configuration 20(3.42.5)
2.10(3.5.3.5)
Symmetry group D5h
Dual polyhedron -
Properties convex
Net
Johnson solid 42 net.png

In geometry, the elongated pentagonal orthobirotunda is one of the Johnson solids (J42). As the name suggests, it can be constructed by elongating a pentagonal orthobirotunda (J34) by inserting a decagonal prism between its congruent halves. Rotating one of the pentagonal rotundae (J6) through 36 degrees before inserting the prism yields the elongated pentagonal gyrobirotunda (J43).

A Johnson solid is one of 92 strictly convex polyhedra that have regular faces but are not uniform (that is, they are not Platonic solids, Archimedean solids, prisms or antiprisms). They were named by Norman Johnson, who first listed these polyhedra in 1966.[1]

Formulae

The following formulae for volume and surface area can be used if all faces are regular, with edge length a:[2]

V=\frac{1}{6}(45+17\sqrt{5}+15\sqrt{5+2\sqrt{5}})a^3\approx21.5297...a^3

A=10+\sqrt{30(10+3\sqrt{5}+\sqrt{75+30\sqrt{5}}})a^2\approx39.306...a^2

References

  1. Lua error in package.lua at line 80: module 'strict' not found..
  2. Stephen Wolfram, "Elongated pentagonal orthobirotunda" from Wolfram Alpha. Retrieved July 26, 2010.

External links


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