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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 .