ANSWER
[tex]\begin{equation*} 14\text{ ft} \end{equation*}[/tex]EXPLANATION
We want to find the perimeter of the flag.
To do this, we have to apply the formula for the perimeter of a square:
[tex]P=4L[/tex]where L = length of the square
Therefore, by substituting the length of the flag into the formula, we have that its perimeter is:
[tex]\begin{gathered} P=4*3\frac{1}{2} \\ \\ P=14\text{ ft} \end{gathered}[/tex]That is the answer.