8a.Truncated icosahedron 12/5
20/6 from truncation of
icosahedron 20/3
Data
The distance from the center of the
icosahedron to the center of the icosahedron triangle is EP 0.76. The
distance from
the center of the truncated icosahedron to the center of the hexagon is
EA 2.27 . These two distances are equal, thus EA
= EP 1/3.
Construction
EP is divided in three equal
parts.
20 hexagons (red) are applied on the icosahedron
triangles. The twelve coners (yellow) are cut off,
resulting in twelve pentagons
(green-blue).

Line
1. Icosahedron, net and solid. .
Line 2. Truncated icosahedron, net and
solid
8b. Truncated icosahedron from truncation of dodecahedron 12/5
Data
The distance from the centre
of the dodecahedron to the center of
the pentagon is EP1.11. The distance from
the
centre of the truncated icosahedron to the centre of the pentagon is
EA ×2.33
These two distances are equal, thus EA = EP 0.48
. The distance between the corner of the
truncated icosahedron pentagon (red) and
the midpoint of the dodecahedron pentagon
is incircle radius of the dodecahedron pentagon minus circum-circle radius
of
the truncated icosahedron pentagon ; Ep 0.69 minus EA 0.86 = EP0.28.
Construction
The pentagons (red) are applied on the
dodecahedron pentagons with the corners directed to
the midpoint of the dodecahedron pentagon
edges
The twenty corners (yellow) of the
dodecahedron are cut off, resulting in
twenty hexagons (green-blue.

Drawing demonstrating the site of the truncated
icosahedron pentagon