A pyramid is a solid formed from a polygonal base and triangular faces that meet at a vertex.
A pyramid is described by the shape of its base. For instance, a triangular pyramid has a base that is a triangle and a pentagonal pyramid has a base that is a pentagon.
A right pyramid has isosceles triangles as its lateral faces and its apex lies directly above the midpoint of the base, otherwise it is an oblique pyramid.
Following are facts about pyramids: