7b. Icosadodecahedron 20/3 12/5 from truncation of dodecahedron 12/5

Data

The distance from the centre of the dodecahedron to the centre of the pentagon is EP×1.11.

The distance from the centre of the icosadodecahedron to the center of the pentagon (red)

is EA×1.38. These two distances are equal, thus EA = EP×0.81.

[ Alternative calculation of EA:

EP is divided in two equal parts. ½EP / EA = 1.618 (Golden section) EA = EP×0.81]

Construction

Twelve pentagons (red) are applied on the original pentagons. The twenty corners(yellow) are cut

off, resulting in twenty triangles (green-blue)

Line 1: Dodecahedron, net and solid. Line 2: Icosadodecahedron, net and solid.