Area = [tex] \pi r ^{2} [/tex]
64 = [tex] \pi r ^{2} [/tex]
[tex] \frac{64}{ \pi } =r^2[/tex]
[tex]r= \frac{ \sqrt{64} }{ \sqrt{ \pi } } = \frac{8}{ \sqrt{ \pi } } [/tex]
If you want the denominator rationalized, the answer is [tex] \frac{8 \sqrt{ \pi } }{ \pi } [/tex]
