Rotunda (geometry)

From Infogalactic: the planetary knowledge core
Jump to: navigation, search
Set of rotundas
Pentagonal rotunda
(Example: pentagonal rotunda)
Faces 1 n-gons
1 2n-gons
n pentagons
2n triangles
Edges 7n
Vertices 4n
Symmetry group Cnv, [n], (*nn), order 2n
Rotation group Cn, [n]+, (nn), order n
Properties convex

In geometry, a rotunda is any member of a family of dihedral-symmetric polyhedra. They are similar to a cupola but instead of alternating squares and triangles, it alternates pentagons and triangles around an axis. The pentagonal rotunda is a Johnson solid.

Other forms can be generated with dihedral symmetry and distorted equilateral pentagons.

See also

References

  • Norman W. Johnson, "Convex Solids with Regular Faces", Canadian Journal of Mathematics, 18, 1966, pages 169–200. Contains the original enumeration of the 92 solids and the conjecture that there are no others.
  • Lua error in package.lua at line 80: module 'strict' not found. The first proof that there are only 92 Johnson solids.

<templatestyles src="Asbox/styles.css"></templatestyles>