The diameter of a ring is 19mm. Calculate the area of the ring in cm^2, giving the area to 3 significant figures.
First you must convert the diameter into cm from mm:19/10 = 1.9cmThen you must find the radius of the ring:radius = diameter/2 = 1.9/2 = 0.95 cmThen you can calculate the area:area = 2πr2 = 2 x π x (0.95)2 = 5.67 cm2
