Answer:
9 meters
Step-by-step explanation:
Area of a square:
[tex]A=s^2[/tex]
There are only 2 variables in this equation, and as A is already given, you can solve for s. Just plug in the given value and go from there:
[tex]A=s^2\\81=s^2\\s^2=81\\s=\sqrt{81}\\s=\pm9[/tex]
You cannot have a negative side length, so the answer here is just 9 meters.
