A pyramid refers to a polyhedron created by joining a polygonal base to triangular lateral faces. There are several types of pyramids, and each is named after the shape of its base. For example, a square pyramid has a square base, and a pentagonal pyramid has a base that is a pentagon.
A pyramid whose base has n sides will have n+1 faces, 2n edges and n+1 vertices. A pyramid whose apex is located directly above the center of the base is referred to as a right pyramid; if the apex is located in any other position, it's an oblique pyramid. If the base of the pyramid is a regular polygon, it can be referred to as a regular pyramid; otherwise it's an Irregular pyramid.
The volume of a pyramid is given by V=1/3Bh, where B is the base area and h is the vertical height from the apex to the base. If all the side faces are the same, the surface area is given by B + 1/2 P*S, where B is the base area, P is the perimeter of the base polygon and S is the slant height of the pyramid. If the side faces are different, simply add the base area to the lateral area.