C = 2πr^2 . Solve for r .

Answer 1

C = 2 pi r^2 solve for r

divide by 2 pi you get

C/ (2 pi) = r^2 square root both sides

r = plus/minus square root of (C/2 pi) usually we do not use the negative value in radius of a circle

Answer 2

C = 2πr²

r² = C/2π (Divide both sides by 2π)

r = √(C/2π) (Square root on both sides)

Answer 3

Treat this just like any other algebra problem.

1. 2π is a multiplier, so divide it away (both sides)
2. C/2π = r²
3. Take the square root of both sides to solve for r
4. r = ± √(C/2π)

Answer 4

The correct equation would be Circumference (C) = 2 * PI * R, however, let's go with what you given.

C = 2 * PI * R^2

divide both sides by 2 * PI to isolate R^2

C/(2*PI) = R^2

Take square root of both sides to get R:

sqrt(C/(2*PI)) = R