It's been about 30 years since I took high school geometry, so my math skills are a little rusty

What is the name of a polyhedron made from 12 pentagons and 60 hexagons (see http://www.georgehart.com/Puzzle2.html) , and how do I calculate the edge length of the faces, from the in-diameter of the polyhedron?

For example, if I want to make such a polygon, with an in-diameter of 3 meters, what would be the edge length of the pentagons/hexagons?