We are given the area of a square and we are asked to find its side length. To do that, let's remember the formula for the area of a square:

Where:

We solve for the side length "l", by taking square roots on both sides:
![\sqrt[]{A}=l](https://img.qammunity.org/2023/formulas/mathematics/college/xdkpypnp4ksyzuaepw62jidaonaigpwiiv.png)
Since we are given that the area is:

Replacing:
![\sqrt[]{82.2}=l](https://img.qammunity.org/2023/formulas/mathematics/college/aerubs42u6f5qab0ixfz2w766mygc7fqlb.png)
Solving the operations:
![9.1\operatorname{cm}=l]()
Therefore, the side length is 9.1 cm.