First we need to find the radius. Using Pythagorean theorem we can find the radius which is the distance between the center and any point along the circle:
r=((5-1)^2+(2-2)^2)^(1/2)
r=(4^2-0^2)^(1/2)
r=4 units.
Circumference=2pr so our circumference is 8p units^2
