[tex]\begin{gathered} \text{Lenght of the square, L = 4}\sqrt[]{5\text{ }}mm \\ \text{Perimeter of the square = 4L = 4 x 4}\sqrt[]{5\text{ }}\text{ =16}\sqrt[]{5}\text{ mm} \\ \text{Area of the square = L}^2\text{ = 4}\sqrt[]{5\text{ }}\text{ x 4}\sqrt[]{5}\text{ =16}\sqrt[]{25\text{ }}=16(5)=80mm^2 \end{gathered}[/tex]
