Elongated triangular cupola

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Elongated triangular cupola
Elongated triangular cupola.png
Type Johnson
J17 - J18 - J19
Faces 1+3 triangles
3.3 squares
1 hexagon
Edges 27
Vertices 15
Vertex configuration 6(42.6)
3(3.4.3.4)
6(3.43)
Symmetry group C3v
Dual polyhedron -
Properties convex
Net
Johnson solid 18 net.png

In geometry, the elongated triangular cupola is one of the Johnson solids (J18). As the name suggests, it can be constructed by elongating a triangular cupola (J3) by attaching a hexagonal prism to its base.

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}(5\sqrt{2}+9\sqrt{3}))a^3\approx3.77659...a^3

A=(9+\frac{5\sqrt{3}}{2})a^2\approx13.3301...a^2

Dual polyhedron

The dual of the elongated triangular cupola has 15 faces: 6 isosceles triangles, 3 rhombi, and 6 quadrilaterals.

Dual elongated triangular cupola Net of dual
160px 160px

Related polyhedra and honeycombs

Johnson solid No.18(Elongated triangular cupola) fill the space with Tetrahedron and Johnson solid No.1(Square pyramid).[3]

References

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External links


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  1. Lua error in package.lua at line 80: module 'strict' not found..
  2. Stephen Wolfram, "Elongated triangular cupola" from Wolfram Alpha. Retrieved July 22, 2010.
  3. http://woodenpolyhedra.web.fc2.com/J18.html