Question

a piece of string is wound tightly round a cylinder for 20 complete turns.the length of the string is found to be 3.96m. Calculate the diameter of the cylinder In cm​

Answer 1

3.96m = 396 cm (because 1m = 100cm)

Now divide 396cm by 20

396/20= 19.8 cm (this is the circumference of the cylinder)

C=2πr

19.8 =2πr

19.8/2π=r (divide 19.8 *circumference with 2π)

r= 3.15cm ( correct to two dp)