Small snub icosicosidodecahedron

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Short description: Geometric figure


Small snub icosicosidodecahedron
Small snub icosicosidodecahedron.png
Type Uniform star polyhedron
Elements F = 112, E = 180
V = 60 (χ = −8)
Faces by sides (40+60){3}+12{5/2}
Wythoff symbol | 5/2 3 3
Symmetry group Ih, [5,3], *532
Index references U32, C41, W110
Dual polyhedron Small hexagonal hexecontahedron
Vertex figure Small snub icosicosidodecahedron vertfig.png
35.5/2
Bowers acronym Seside

File:Small snub icosicosidododecahedron.stl

In geometry, the small snub icosicosidodecahedron or snub disicosidodecahedron is a uniform star polyhedron, indexed as U32. It has 112 faces (100 triangles and 12 pentagrams), 180 edges, and 60 vertices. Its stellation core is a truncated pentakis dodecahedron. It also called a holosnub icosahedron, ß{3,5}.

The 40 non-snub triangular faces form 20 coplanar pairs, forming star hexagons that are not quite regular. Unlike most snub polyhedra, it has reflection symmetries.

Convex hull

Its convex hull is a nonuniform truncated icosahedron.

Truncated icosahedron.png
Truncated icosahedron
(regular faces)
Small snub icosicosidodecahedron convex hull.png
Convex hull
(isogonal hexagons)
Small snub icosicosidodecahedron.png
Small snub icosicosidodecahedron

Cartesian coordinates

Cartesian coordinates for the vertices of a small snub icosicosidodecahedron are all the even permutations of [math]\displaystyle{ \begin{array}{clllc} \Bigl(& \pm \bigl[1-\varphi+\alpha\bigr],& \ \ \ \, 0,& \pm \bigl[3+\varphi\alpha\bigr] &\Bigr) \\ \Bigl(& \pm \bigl[\varphi-1+\alpha\bigr],& \pm\,2,& \pm \bigl[2\varphi-1+\varphi\alpha\bigr] &\Bigr) \\ \Bigl(& \pm \bigl[\varphi+1+\alpha\bigr],& \pm\,2\bigl[\varphi-1\bigr],& \pm \bigl[1+\varphi\alpha\bigr] &\Bigr) \end{array} }[/math]

where [math]\displaystyle{ \varphi = \tfrac{1+ \sqrt 5}{2} }[/math] is the golden ratio and [math]\displaystyle{ \alpha = \sqrt{3\varphi - 2}. }[/math]

See also

External links