Question

A= 4 π r ^2 make r the subject

Answer 1

Hello !

Answer:

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

Explanation:

We will isolate r and express it in terms of A, 4, and π.

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Given equality:

`\sf A = 4\pi r^2`

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Divide both sides of the equality by 4π.

`\sf (A)/(4\pi) = (4 \pi r^2)/(4\pi) \\ \\ \sf (A)/(4 \pi) = r^2`

Take the square root.

`\sf \sqrt{(A)/(4\pi)}= √(r^2) \\ \\ \implies \boxed{\sf r = \sqrt{(A)/(4\pi)}}`

Have a nice day ;)