Answer:
[tex]\boxed {\tt A= 81 \ ft^2}[/tex]
Step-by-step explanation:
The area of a square can be found using the following formula:
[tex]A=s^2[/tex]
where [tex]s[/tex] is the side length.
We know the side length is 9 feet.
[tex]s= 9 \ ft[/tex]
Substitute the value into the formula.
[tex]A=(9 \ ft)^2[/tex]
Evaluate the exponent.
[tex]A= 81 \ ft^2[/tex]
The area of the square is 81 feet squared.