A solid having a polygonal base with n sides, each side forming the base of a triangle. The n triangles so formed have a common vertex. The axis of the pyramid is a line joining the vertex to the centre of symmetry of the base. If the axis is perpendicular to the base the solid is a right pyramid. A square pyramid has a square base and a triangular pyramid has a triangular base (see tetrahedron). The volume of a pyramid is one third of the base area multiplied by the height.
Subjects: Physics — Mathematics.