The Surface Area of a Rectangular Solid is more annoying to calculate than the surface area of a cube, but, on the bright side, rectangular solids give us the opportunity to make pretty visuals.

The area of the blue side is $xz$, the area of the pink side is $yz$, and the area of the yellow side is $xy$. But remember, we have two of each side! So the surface area formula is simply:

$$2xz + 2yz + 2xy = 2(xz + yz + xy)$$

Example

What is the surface area of a rectangular solid that is $6$ inches wide, $11$ inches tall, and $4$ inches deep?

$$2(6 \times 11 + 6 \times 4 + 11 \times 4)$$

$$2(66 + 24 + 44)$$

$$2(134) = 268 \ in^2$$