Hello, ClutchUSMC!
You are putting in a 20ft x 30ft rectangular pool.
Your pool will be surrounded by a concrete sidewalk of uniform width and 3 inches thick.
Write an expression in terms of
for the volume of concrete in the sidewalk.
Explain how you got your expression. I assume that
is the width of the sidewalk. Code:
: x : - 30 - : x :
- * - - - - - - - - * - -
x | | :
- | * - - - - * | :
: | | | | :
20 | |20 | | 20+2x
: | | 30 | | :
- | * - - - - * | :
x | | :
- * - - - - - - - - * - -
: - - 30+2x - - :
The total area is: .
ft²
The pool area is: .
ft²
The area of the sidewalk is: .
ft²
The thickness of the sidewalk is: . 
Therefore, the volume of the concrete is: .
ft³