Recall that the perimeter of a square is determined by the formula
[tex]\begin{gathered} 4s=P_{\text{square}} \\ \text{where} \\ s\text{ is the side length of the square} \end{gathered}[/tex]Given that the perimeter is 64 mm, using the formula the side is calculated as
[tex]\begin{gathered} 4s=P \\ 4s=64 \\ \frac{4s}{4}=\frac{64}{4} \\ s=16\text{ mm} \end{gathered}[/tex]Therefore, the length of each side of the square is 16 mm.
