Consider the right prism as shown in the figure. There are as many cubic units in each layer parallel to the base as there are square units in the area of the base. Also, there are many layers of cubic units in the prism as there are linear units in the altitudes. We can, therefore, find the total number of cubic units in the prism by multiplying the area of the base by the altitude.

Rule: The volume of the prism equals its base times its altitude.

Example:
            The base of a right prism is an equilateral triangle with a side of cm and its heights is cm, find its volume.
Solution:
            Volume,          
                        Since, base is an equilateral triangle
                    cm
                                    cm
                     Cubic cm

Example:
            The sides of a triangular prism are cm, cm and cm respectively. The volume of the prism is cubic cm. What is its height?
Solution:
            Now,  
                   
                     
                             Square cm
                   
                               cm