Compound of dodecahedron and icosahedron

{{Short description|Polyhedral compound}}

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!bgcolor=#e7dcc3 colspan=2|First stellation of icosidodecahedron

align=center colspan=2|240px
bgcolor=#e7dcc3|TypeDual compound
bgcolor=#e7dcc3|Coxeter diagram{{CDD|nodes_10ru|split2-53|node}} ∪ {{CDD|nodes_01rd|split2-53|node}}
bgcolor=#e7dcc3|Stellation coreicosidodecahedron
bgcolor=#e7dcc3|Convex hullRhombic triacontahedron
bgcolor=#e7dcc3|IndexW47
bgcolor=#e7dcc3|Polyhedra1 icosahedron
1 dodecahedron
bgcolor=#e7dcc3|Faces20 triangles
12 pentagons
bgcolor=#e7dcc3|Edges60
bgcolor=#e7dcc3|Vertices32
bgcolor=#e7dcc3|Symmetry groupicosahedral (Ih)

In geometry, this polyhedron can be seen as either a polyhedral stellation or a compound.

As a compound

It can be seen as the compound of an icosahedron and dodecahedron. It is one of four compounds constructed from a Platonic solid or Kepler-Poinsot solid, and its dual.

It has icosahedral symmetry (Ih) and the same vertex arrangement as a rhombic triacontahedron.

This can be seen as the three-dimensional equivalent of the compound of two pentagons ({10/2} "decagram"); this series continues into the fourth dimension as the compound of 120-cell and 600-cell and into higher dimensions as compounds of hyperbolic tilings.

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|{{multiple image

| align = left | total_width = 400

| image2 = Polyhedron 12.png |width2=1|height2=1

| image3 = Polyhedron 20.png |width3=1|height3=1

| footer = A dodecahedron and its dual icosahedron

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|{{multiple image

| align = left | total_width = 400

| image2 = Polyhedron 12-20 blue.png |width2=1|height2=1

| image3 = Polyhedron 12-20 dual blue.png |width3=1|height3=1

| footer = The intersection of both solids is the icosidodecahedron, and their convex hull is the rhombic triacontahedron.

}}

{{multiple image

| align = left | total_width = 700

| image2 = Polyhedron pair 12-20 from blue.png |width2=1|height2=1

| image3 = Polyhedron pair 12-20 from yellow.png |width3=1|height3=1

| image4 = Polyhedron pair 12-20 from red.png |width4=1|height4=1

| footer = Seen from 2-fold, 3-fold and 5-fold symmetry axes
The decagon on the right is the Petrie polygon of both solids.

}}

{{multiple image

| align = right | total_width = 320

| image2 = Polyhedron pair 12-20 big.png |width2=1|height2=1

| image3 = Polyhedron small rhombi 12-20 dual max.png |width3=1|height3=1

| footer = If the edge crossings were vertices, the mapping on a sphere would be the same as that of a deltoidal hexecontahedron.

}}

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As a stellation

This polyhedron is the first stellation of the icosidodecahedron, and given as Wenninger model index 47.

The stellation facets for construction are:

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As a Faceting

The compound of a Dodecahedron and an Icosahedron shares the same vertices as a list of other polyhedra, including the Rhombic triacontahedron and the Small triambic icosahedron.

See also

References

  • {{cite book | first=Magnus | last=Wenninger | authorlink=Magnus Wenninger | title=Polyhedron Models | publisher=Cambridge University Press | year=1974 | isbn=0-521-09859-9 }}