ANSWER:
$2,970
Explanation:
We only have to take into account the 4 walls of the building.
Now, there are 2 types of walls, one is 12 feet and the other is 15 feet, both with a height of 10 feet.
We calculate the area, adding the area of each type of wall, knowing that there are 2 per type of wall, like this:
![\begin{gathered} W_1=12\cdot10=120\rightarrow\text{ 2 Walls}\rightarrow240\text{ ft}^2 \\ \\ W_2=15\cdot10=150\operatorname{\rightarrow}\text{2 Walls}\operatorname{\rightarrow}300\text{ ft}^2 \\ \\ \text{ Total }=240+300=540\text{ ft}^2 \end{gathered}]()
Now, we know the cost per square foot ($5.50), we multiply by this value:

It cost $2,970 to build the storage building