3378.1376=4*3.14r^2

Solution for 3378.1376=4*3.14r^2 equation:

Simplifying
3378.1376 = 4 * 3.14r2

Multiply 4 * 3.14
3378.1376 = 12.56r2

Solving
3378.1376 = 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.
3378.1376 + -12.56r2 = 12.56r2 + -12.56r2

Combine like terms: 12.56r2 + -12.56r2 = 0.00
3378.1376 + -12.56r2 = 0.00

Add '-3378.1376' to each side of the equation.
3378.1376 + -3378.1376 + -12.56r2 = 0.00 + -3378.1376

Combine like terms: 3378.1376 + -3378.1376 = 0.0000
0.0000 + -12.56r2 = 0.00 + -3378.1376
-12.56r2 = 0.00 + -3378.1376

Combine like terms: 0.00 + -3378.1376 = -3378.1376
-12.56r2 = -3378.1376

Divide each side by '-12.56'.
r2 = 268.96

Simplifying
r2 = 268.96

Take the square root of each side:
r = {-16.4, 16.4}