I am deciphering a CSS code that Ana Tudor Maria has done. http://codepen.io/thebabydino/pen/qIfbL
In her example, she has a formula that calculates the distance between 2 opposite faces. I have no idea what she is referring to when she said faces. They are many faces in a dodecahedron net.
This is the formula that she used: Distance = (half diagonal of first rhombus + distance between rhombi centres)*sin(pi() - dihedral angle)
I have asked the author but I haven't gotten a reply yet.