I need help on a problem that's on formula for circumference. A circle has a circumference of 36 cm. find it's radius .but it says give an exact answer in simplest form and it says enter pi for the symbol of pie .
C = pi * r^2
36 = 3.14 * r^2
36/3.14 = r^2
11.464968 = r^2
3.3859958 = r