The Icosahedron
The surface of an Icosahedron consists of twenty equilateral triangles and is therefore one of the five Platonic solids.
The following elements of a Icosahedron are calculated if one of them is given:
- Edge a
- Apothem h1
- Altitude h2
- Circumradius ru
- Inradius ri
- Volume V
- Surface S
Example 1:
Given:
¯¯¯¯¯
Apothem h1 = 1,5
Results:
¯¯¯¯¯¯¯
Edge a = 1,7320508
Altitude h2 = 3,2945564
Circumradius rc = 1,6472782
Inradius ri = 1,309017
Volume V = 11,33642
Surface S = 25,980762
Example 2:
Given:
¯¯¯¯¯
Edge a = sqrt(3)
Results:
¯¯¯¯¯¯¯
Apothem h1 = 1,5
Altitude h2 = 3,2945564
Circumradius rc = 1,6472782
Inradius ri = 1,309017
Volume V = 11,33642
Surface S = 25,980762
See also:
Graphics 3DWikipedia: Platonic solid

