The area of a square can be found by using the following expression:

where "A" is the area and "l" is the length of each side of the square. The square on this problem has an area of 9 cm², so we can find the sides by replacing A for 9 on the expression above.

To solve it we need to take the square root on both sides of the equation.
![\begin{gathered} \sqrt[]{l^2}=\sqrt[]{9} \\ l=\sqrt[]{9} \\ l=3\text{ cm} \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/high-school/vphp964omndw0rhz0jgcin7373v1exozhr.png)
Each side of the square has a length of 3 cm, so the sides are 3 cm x 3 cm.