Question

I need to know the process and the answer and how to get it

Answer 1

Solution

We have the following expression:

$A=3.14r^{2}$

We can divide both sides by 3.14 and we got

$\frac{A}{3.14}=r^{2}$

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

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