To find the distance around a circular disc, multiply the diameter of the disc by 3.14. What is the distance around the disc when :
(a) the diameter is 18.7 cm?
(b) the radius is 6.45 cm?
(a) 58.718 cm
(b) 40.506 cm
Circumference \(\approx 3.14\times d\). (a) \(3.14\times18.7=58.718\) cm. (b) \(d=2r=12.9\) cm, so \(3.14\times12.9=40.506\) cm.