Question

An equation is given.

​A=4π r2
​Solve the equation for r .

A) r=4πA2
B) r=A2π
C) r=A4π−−√
D) r=4πA−−√

Answer 1

r =
`\sqrt{(A)/(4\pi ) }`

Explanation:

Given

A = 4πr² ( divide both sides by 4π )

`(A)/(4\pi )` = r² ( take the square root of both sides )

`\sqrt{(A)/(4\pi ) }` = r