Inverted snub dodecadodecahedron

The inverted snub dodecadodecahedron or isdid, is a uniform polyhedron. It consists of 60 snub triangles, 12 pentagrams, and 12 pentagons. Three triangles, 1 pentagon, and one pentagram meeting at each vertex. It can be constructed by alternation of the quasitruncated dodecadodecahedron and then setting all edge lengths to be equal.

Measures
The circumradius R ≈ 0.85163 of the inverted snub dodecadodecahedron with unit edge length is the smallest positive real root of:
 * $$64x^8-192x^6+180x^4-65x^2+8.$$

Its volume V ≈ 4.61431 is given by the smallest positive real root of:
 * $$64x^8-21440x^6+18100x^4+5895625x^2+60062500.$$

These same polynomials define the circumradius and volume of the snub dodecadodecahedron.

Related polyhedra
The inverted disnub dodecadodecahedron is a uniform polyhedron compound composed of the 2 opposite chiral forms of the inverted snub dodecadodecahedron.