We have been given the dimensions of the rectangular prism. 
Lets say that the length, width, and height of the rectangular prism are: 
Length 
 
 
Width 

Height

Volume of a rectangular prism is given by: 

Plugging the values of length, width, and height, we get: 
Total volume of the prism 

 (we have used
 (we have used 
 )
)
So, the expression for the total volume of the prism is: 
