五角锥是指底面为五边形的锥体

底面为正五边形的五角锥称为正五角锥

底面为有一个角大于180°的五角锥称为凹五角锥

如果底面为每一个角都小于180°的五角锥称为凸五角锥

In geometry, a pentagonal pyramid is a pyramid with a pentagonal base upon which are erected five triangular faces that meet at a point (the vertex). Like any pyramid, it is self-dual.

The regular pentagonal pyramid has a base that is a regular pentagon and lateral faces that are equilateral triangles. It is one of the Johnson solids (J₂). Its height H, from the midpoint of the pentagonal face to the apex, (as a function of a, where a is the side length), can be computed as: