Question

sam built a large wooden storage box. the box was in the shape of a rectangular prism, as shown below. he covered all the sides of the box with special wallpaper that cost a total of $354. how much did the wallpaper cost per square foot? 2 ft 5 ft 7 ft

Explanation:

Step1: Calculate surface - area of rectangular prism

The surface - area formula of a rectangular prism is $SA = 2(lw+lh + wh)$, where $l = 5$ ft, $w = 2$ ft, and $h = 7$ ft.
$SA=2(5\times2 + 5\times7+2\times7)$
$=2(10 + 35+14)$
$=2\times59$
$ = 118$ square feet.

Step2: Calculate cost per square - foot

The total cost of wallpaper is $354$. Let the cost per square - foot be $x$. We know that $\text{Total cost}=\text{Cost per square - foot}\times\text{Surface area}$. So, $x=\frac{354}{118}$.
$x = 3$ dollars per square foot.

Answer:

3