72.345597=3.14*r^2

Solution for 72.345597=3.14*r^2 equation:

Simplifying
72.345597 = 3.14r2

Solving
72.345597 = 3.14r2

Solving for variable 'r'.

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

Add '-3.14r2' to each side of the equation.
72.345597 + -3.14r2 = 3.14r2 + -3.14r2

Combine like terms: 3.14r2 + -3.14r2 = 0.00
72.345597 + -3.14r2 = 0.00

Add '-72.345597' to each side of the equation.
72.345597 + -72.345597 + -3.14r2 = 0.00 + -72.345597

Combine like terms: 72.345597 + -72.345597 = 0.000000
0.000000 + -3.14r2 = 0.00 + -72.345597
-3.14r2 = 0.00 + -72.345597

Combine like terms: 0.00 + -72.345597 = -72.345597
-3.14r2 = -72.345597

Divide each side by '-3.14'.
r2 = 23.03999904

Simplifying
r2 = 23.03999904

Take the square root of each side:
r = {-4.7999999, 4.7999999}