Given:
A figure of a rectangular prism with length l, width w and height h.
To find:
The surface area of the rectangular prism.
Solution:
The product of twice of the length l and the width w is:
...(i)
The product of twice of the length l and the height is:
...(ii)
The product of twice of the width w and the height h is:
...(iii)
The surface area of the prism is the sum of (i), (ii) and (iii). So, the expression for the surface area is:
Therefore, the required expression is .