Rotunda (geometry)
| Set of rotundas | |
|---|---|
(Example: pentagonal rotunda) | |
| Faces | 1 n-gon 1 2n-gon 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.