1808.64=4(3.14)r^2

Solution for 1808.64=4(3.14)r^2 equation:

Simplifying
1808.64 = 4(3.14) * r2

Multiply 4 * 3.14
1808.64 = 12.56r2

Solving
1808.64 = 12.56r2

Solving for variable 'r'.

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

Add '-12.56r2' to each side of the equation.
1808.64 + -12.56r2 = 12.56r2 + -12.56r2

Combine like terms: 12.56r2 + -12.56r2 = 0.00
1808.64 + -12.56r2 = 0.00

Add '-1808.64' to each side of the equation.
1808.64 + -1808.64 + -12.56r2 = 0.00 + -1808.64

Combine like terms: 1808.64 + -1808.64 = 0.00
0.00 + -12.56r2 = 0.00 + -1808.64
-12.56r2 = 0.00 + -1808.64

Combine like terms: 0.00 + -1808.64 = -1808.64
-12.56r2 = -1808.64

Divide each side by '-12.56'.
r2 = 144

Simplifying
r2 = 144

Take the square root of each side:
r = {-12, 12}