circumference=diamter times pi
diamter=2 times radius
circumference=radius times 2 times pi
circunference=135.648
aprox pi to 3.14
subsitute
135.648=radius times 2 times 3.14
135.648=radius times 6.28
divide both sides by 6.28
21.6=radius
aswe ris radous=21.6 units
