Icositruncated_dodecadodecahedron Knowpia

Icositruncated dodecadodecahedron

Type	Uniform star polyhedron
Elements	F = 44, E = 180 V = 120 (χ = −16)
Faces by sides	20{6}+12{10}+12{10/3}
Coxeter diagram
Wythoff symbol	3 5 5/3 \|
Symmetry group	I_h, [5,3], *532
Index references	U₄₅, C₅₇, W₈₄
Dual polyhedron	Tridyakis icosahedron
Vertex figure	6.10.10/3
Bowers acronym	Idtid

In geometry, the icositruncated dodecadodecahedron or icosidodecatruncated icosidodecahedron is a nonconvex uniform polyhedron, indexed as U₄₅.

Convex hull edit

Its convex hull is a nonuniform truncated icosidodecahedron.

Truncated icosidodecahedron	Convex hull	Icositruncated dodecadodecahedron

Cartesian coordinates edit

Cartesian coordinates for the vertices of an icositruncated dodecadodecahedron are all the even permutations of

{\begin{array}{crrlc}{\Bigl (}&\pm {\bigl [}2-{\frac {1}{\varphi }}{\bigr ]},&\pm \,1,&\pm {\bigl [}2+\varphi {\bigr ]}&{\Bigr )},\\{\Bigl (}&\pm \,1,&\pm \,{\frac {1}{\varphi ^{2}}},&\pm {\bigl [}3\varphi -1{\bigr ]}&{\Bigr )},\\{\Bigl (}&\pm \,2,&\pm \,{\frac {2}{\varphi }},&\pm \,2\varphi &{\Bigr )},\\{\Bigl (}&\pm \,3,&\pm \,{\frac {1}{\varphi ^{2}}},&\pm \,\varphi ^{2}&{\Bigr )},\\{\Bigl (}&\pm \,\varphi ^{2},&\pm \,1,&\pm {\bigl [}3\varphi -2{\bigr ]}&{\Bigr )},\end{array}}

where $\varphi ={\tfrac {1+{\sqrt {5}}}{2}}$ is the golden ratio.

Related polyhedra edit

Tridyakis icosahedron edit

Tridyakis icosahedron

Type	Star polyhedron
Face
Elements	F = 120, E = 180 V = 44 (χ = −16)
Symmetry group	I_h, [5,3], *532
Index references	DU₄₅
dual polyhedron	Icositruncated dodecadodecahedron

The tridyakis icosahedron is the dual polyhedron of the icositruncated dodecadodecahedron. It has 44 vertices, 180 edges, and 120 scalene triangular faces.

References edit

Wenninger, Magnus (1983), Dual Models, Cambridge University Press, ISBN 978-0-521-54325-5, MR 0730208 Photo on page 96, Dorman Luke construction and stellation pattern on page 97.

External links edit

Weisstein, Eric W. "Icositruncated dodecadodecahedron". MathWorld.