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

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	Ih, [5,3], *532
Index references	U45, C57, W84
Dual polyhedron	Tridyakis icosahedron
Vertex figure	6.10.10/3
Bowers acronym	Idtid

Its convex hull is a nonuniform truncated icosidodecahedron.

Truncated icosidodecahedron

Convex hull

Icositruncated dodecadodecahedron

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

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

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

• Catalan solid Duals to convex uniform polyhedra
• Uniform polyhedra
• List of uniform polyhedra

• 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.

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

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