We define the number π as the ratio between the circumference and diameter of a circle: π = c/d. Rearranging this equation gives us one for the circumference: c = πd. Using an approximation of π ≈ 3.14 and our value of d = 18 feet, we can find that c = 3.14(18) = 56.52ft, or 56.5 ft, rounded to the nearest tenth.
