108=3.14(r^2)12

Solution for 108=3.14(r^2)12 equation:

Simplifying
108 = 3.14(r2) * 12

Reorder the terms for easier multiplication:
108 = 3.14 * 12r2

Multiply 3.14 * 12
108 = 37.68r2

Solving
108 = 37.68r2

Solving for variable 'r'.

Move all terms containing r to the left, all other terms to the right.

Add '-37.68r2' to each side of the equation.
108 + -37.68r2 = 37.68r2 + -37.68r2

Combine like terms: 37.68r2 + -37.68r2 = 0.00
108 + -37.68r2 = 0.00

Add '-108' to each side of the equation.
108 + -108 + -37.68r2 = 0.00 + -108

Combine like terms: 108 + -108 = 0
0 + -37.68r2 = 0.00 + -108
-37.68r2 = 0.00 + -108

Combine like terms: 0.00 + -108 = -108
-37.68r2 = -108

Divide each side by '-37.68'.
r2 = 2.866242038

Simplifying
r2 = 2.866242038

Take the square root of each side:
r = {-1.692997944, 1.692997944}