The Compendium Geometry is an eBook providing facts, formulas and explanations about geometry.


The regular octahedron is a square dipyramid which consists of eight equilateral triangular faces and is one of the Platonic solids.

For an octahedron with edge length a the height h is

Its volume V is given by

its surface is

The radii of the circumscribed (rc) and inscribed (ri) spheres are


Last Update: 2010-12-06