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A dodecahedron is a regular polyhedron, one of the five three-dimensional platonic solids, and has twelve congruent pentagonal faces. It has a schläfli symbol of $\{5, 3\}$, meaning that 3 pentagons join at each vertex. It is the dual of the icosahedron.

Under the elemental naming scheme, it is called a cosmogon.

Properties

It is possible to inscribe 5 cubes into a dodecahedron such that all of the edges of the cubes are diagonals of the dodecahedron's faces.

It is also the only platonic solid to have pentagonal faces.

Subfacets and Structure

Structure

The dodecahedron has 12 pentagonal faces, joining three to a vertex. When seen face first, the layers start with one face, then the five surrounding it, then five more, and finally the opposite face.

Hypervolumes

• vertex count = $20$
• edge length = $30l$
• surface area = $3{ l }^{ 2 }\sqrt { 5(5+2\sqrt { 5 }) }$
• surcell volume = $\frac { 15+7\sqrt { 5 } }{ 4 } { l }^{ 3 }$

Subfacets

$\{2,3\}$ $\{3,3\}$ $\{4,3\}$ $\{5,3\}$ $\{6,3\}$ $\{7,3\}$ $\{8,3\}$ ... $\{\aleph_0,3\}$
Trigonal hosohedron Tetrahedron Cube Dodecahedron Hexagonal tiling Order-3 heptagonal tiling Order-3 octagonal tiling ... Order-3 apeirogonal tiling
$\{5,2\}$ $\{5,3\}$ $\{5,4\}$ $\{5,5\}$ $\{5,6\}$ ... $\{5,\aleph_0\}$
Pentagonal dihedron Dodecahedron Order-4 pentagonal tiling Order-5 pentagonal tiling Order-6 pentagonal tiling ... Infinite-order pentagonal tiling
Regular
$t_0 \{5,3\}$
Rectified
$t_1 \{5,3\}$
Birectified
$t_2 \{5,3\}$
Truncated
$t_{0,1} \{5,3\}$
Bitruncated
$t_{1,2} \{5,3\}$
Cantellated
$t_{0,2} \{5,3\}$
Cantitruncated
$t_{0,1,2} \{5,3\}$
Dodecahedron Icosidodecahedron Icosahedron Truncated dodecahedron Truncated icosahedron Rhombicosidodecahedron Great rhombicosidodecahedron
Zeroth First Second Third Fourth Fifth
Cosmotopes Point Line segment Pentagon Dodecahedron Hecatonicosachoron Order-3 Hecatonicosachoron honeycomb
Hydrotopes Point Line segment Pentagon Icosahedron Hexacosichoron Order-5 Pentachoron honeycomb