Great hexagonal hexecontahedron

Great hexagonal hexecontahedron
File:DU64 great hexagonal hexecontahedron.png
Type	Star polyhedron
Face	File:DU64 facets.png
Elements	F = 60, E = 180 V = 104 (χ = −16)
Symmetry group	I, [5,3]+, 532
Index references	DU64
dual polyhedron	Great snub dodecicosidodecahedron

File:Great hexagonal hexecontahedron.stl

3D model of a great hexagonal hexecontahedron

In geometry, the great hexagonal hexecontahedron (or great astroid ditriacontahedron) is a nonconvex isohedral polyhedron. It is the dual of the uniform great snub dodecicosidodecahedron. It is partially degenerate, having coincident vertices, as its dual has coplanar pentagrammic faces.

Proportions

The faces are nonconvex hexagons. Denoting the golden ratio by $\varphi$, the hexagons have one angle of $\arccos (-{\varphi }^{-1})\approx 128.17270762701^{\circ }$, one of $360^{\circ }-\arccos (-{\varphi }^{-1})\approx 231.82729237299^{\circ }$, and four angles of $90^{\circ }$. They have two long edges, two of medium length and two short ones. If the long edges have length $2$, the medium ones have length $1+{\varphi }^{-3/2}\approx 1.48586827176$ and the short ones $1-{\varphi }^{-3/2}\approx 0.51413172824$. The dihedral angle equals $90^{\circ }$.