Question

Reynaldo has a brick with the dimensions shown. He plans to paint the brick to use as a doorstop. What is the total surface area to be painted? Show your work.

8 in. 5.5 in. 3 in.​

Answer 1

169 square inches

Explanation:

You want the total surface area of a brick with dimensions 8 in by 5.5 in by 3 in.

Formula

The formula for the surface area of a rectangular prism can be written as ...

A = 2(LW +H(L+W))

Application

Using the given dimensions, we find the area to be ...

A = 2((8 in)(5.5 in) + (3 in)(8 in +5.5 in)) = 2(44 in² +(3)(13.5) in²)

= 2(44 in² +40.5 in²) = 2(84.5 in²)

= 169 in²

The total surface area to be painted is 169 square inches.