ANSWER
[tex]\operatorname{\$}192.51[/tex]EXPLANATION
First, we have to find the area of the rectangular floor by applying the formula for the area of a rectangle:
[tex]A=L*W[/tex]where L = length
W = width
Therefore, the area of the rectangle is:
[tex]\begin{gathered} A=9*15.5 \\ A=139.5\text{ }ft^2 \end{gathered}[/tex]Now, find the cost by finding the product of the area of the floor and the cost per unit area:
[tex]\begin{gathered} 139.5*1.38 \\ \$192.51 \end{gathered}[/tex]That is the answer.