c=2*3.14*r so first you would divide 13.5 by two to get the radius and you'd get 6.75. then you would plug the into the equation and get the equation c=2*3.14*6.75 . 2*3.14= 6.28 and 6.28*6.75= 42.39. so the perimeter/circumference is 42.39 meters
Sorry if its not right, but im 99.999999% sure it is so yeah
