Question

If you know the area of a circle, how can you find it's radius?​

Answer 1

see explanation

Explanation:

The area (A) of a circle = πr² ← r is the radius

If A is given then to find r

πr² = A ( isolate r² by dividing both sides by π )

r² =
`(A)/(\pi )`

Take the square root of both sides

r =
`\sqrt{(A)/(\pi ) }`

Answer 2

You have the correct idea. The area A of a circle is given by A = π r2 where r is the radius of the circle and π is approximately 3.1416. Dividing both sides of this equation by π gives A/π = r2 and hence if you know A, divide it by π and then take the square root to find r.