Types of solids

5.    Prism :  A solid whose base and top are identical polygons and side faces are rectangles, is called a prism. In a square prism whose base and top are congruent squares. Cuboid, cube etc.
are all special types of prisms.        

6.    Pyramid : A solid whose base is any polygon and side faces are triangles, is called a pyramid. Figure shows a pentagonal pyramid.

7.    Triangular Pyramid :  A triangular pyramid (Tetrahedron) shown in fig. has :

(i)     4 faces    
(ii)     6 edges                                        
(iii)     4 vertices