SEARCH HOME
 Math Central Quandaries & Queries
 Question from Ally: A cylinder has a diameter of 3.5 cm. How many times will a thread 143mm go round the cylinder?

Hi Ally,

I think you should have both measurements in the same units so express the diameter in millimeters.

If $C$ is the circumference of a circle and $d$ is its diameter then $C = \pi\;d.$ What is the circumference of your cylinder? How many times will a thread of length 143 mm go around that circumference?

Penny

Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences.