Elongated triangular bipyramid

Elongated triangular bipyramid
Type	Johnson J13 - J14 - J15
Faces	6 triangles 3 squares
Edges	15
Vertices	8
Vertex configuration	2(33) 6(32.42)
Symmetry group	D3h
Dual polyhedron	Triangular bifrustum
Properties	convex
Net

In geometry, the elongated triangular bipyramid (or dipyramid) is one of the Johnson solids (J₁₄). As the name suggests, it can be constructed by elongating a triangular bipyramid (J₁₂) by inserting a triangular prism between its congruent halves.

The 92 Johnson solids were named and described by Norman Johnson in 1966.

Formulae

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

$V=({\frac {1}{12}}(2{\sqrt {2}}+3{\sqrt {3}}))a\approx 0.668715...a$

$A=({\frac {3}{2}}(2+{\sqrt {3}}))a\approx 5.59808...a$

External links

• Weisstein, Eric W. "Johnson solid". MathWorld.
• Weisstein, Eric W. "Elongated triangular bipyramid". MathWorld.