Rearrange the formula a = π(r2 − r2) for r.

ANSWER



EXPLANATION

We want to rearrange the formula,


for


This means that, we will isolate

so that, it will be on one side of the equation, while the others are also on the other side of the equation.

We must first divide through by π to obtain,



We add


to both sides to obtain,



We now take the square root of both sides to obtain,



We simplify further to obtain,