Respuesta :

Answer:

r = [tex]\sqrt{\frac{A}{4\pi } }[/tex]

Step-by-step explanation:

Given

A = 4πr² ( divide both sides by 4π )

[tex]\frac{A}{4\pi }[/tex] = r² ( take the square root of both sides )

[tex]\sqrt{\frac{A}{4\pi } }[/tex] = r