Respuesta :

Solution

We have the following expression:

[tex]A=3.14r^{2}[/tex]

We can divide both sides by 3.14 and we got

[tex]\frac{A}{3.14}=r^{2}[/tex]

Then we can take square root in both sides and we have:

[tex]r=\pm\sqrt[]{\frac{A}{3.14}}[/tex]