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:

• The bases are polygons such as triangles, squares etc.
• The lateral faces are triangles.
• The number of lateral faces is the same as the number of sides of the base.
• The height is the perpendicular distance from the vertex to the base.
• The slant height is the altitude of any lateral face from the vertex.