

Icosahedron
Try this
Click on the figure to stop rotation. Drag anywhere to rotate.
An icosahedron is a regular polyhedron that has 20
faces.
All the faces are
equilateral triangles
and are all
congruent,
that is, all the same size. It is one of the five
Platonic solids.
Surface area
If s is the length of any edge, then each face has an area given by:
Since there are 20 faces, when we multiply the above by 20 and simplify, we get the surface area of the whole object. As the formula:
Volume
If s is the length of any edge, then the volume enclosed by the icosahedron is given by the formula:
Related topics
(C) 2011 Copyright Math Open Reference. All rights reserved

