Inverted disnub dodecadodecahedron

The inverted disnub dodecadodecahedron, idisdid, or compound of two inverted snub dodecadodecahedra is a uniform polyhedron compound. It consists of 120 snub triangles, 24 pentagons, and 24 pentagrams (the latter two can combine in pairs due to faces in the same plane). Three triangles, one pentagon, and one pentagram join at each vertex.

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

Its volume V ≈ 9.22862 is given by twice the smallest positive real root of:
 * $$64x^8-21440x^6+18100x^4+5895625x^2+60062500.$$