Rhombicosahedron

The Uniform Polyhedron $U_{56}$ whose Dual Polyhedron is the Rhombicosacron. It has Wythoff Symbol $2\,3\,{{\textstyle{5\over 4}}\atop{\textstyle{5\over 2}}}$. Its faces are $20\{6\}+30\{4\}$. The Circumradius for unit edge length is

$$R={\textstyle{1\over 2}}\sqrt{7}\,.$$

References

Wenninger, M. J. Polyhedron Models. Cambridge, England: Cambridge University Press, pp. 149-150, 1971.