Recall that to evaluate an equation at a given value, we substitute the variable by the given value.
Also, recall that:
[tex](ab)^2=a^2b^2.^{}[/tex]
Therefore, substituting s=8ft in
[tex]A=s^2,[/tex]
we get:
[tex]A=(8ft)^2\text{.}[/tex]
Simplifying the above equation we get:
[tex]\begin{gathered} A=8^2ft^2, \\ A=64ft^2\text{.} \end{gathered}[/tex]
Answer: Option A.
