To solve for r, we need to follow the next steps:
A = 3.14 * r^2
First, divide each side of the equation by 3.14:
(A / 3.14 ) =( 3.14/3.14) * r^2
We know that (3.14 / 3.14 = 1)
(A / 3.14 ) = 1 * r^2
(A / 3.14 ) = r^2
r^2 = ( A / 3.14)
We also need to take the square root to both sides of the previous expression:
sqrt( r^2) = sqrt ( A / 3.14 )
The square root of a number raised to the second power is the same number, that is, sqrt( r^2) = r. Then
r = sqrt ( A / 3.14 )
Therefore, solving the formula for r, we have that:
r = sqrt ( A / 3.14 )
r = sqrt ( A / pi )
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r = V ( A / pi