Find the circumference of a circle that has a diameter of 40 in round to the nearest inch?
Twice pi multiplied by the radius will get you the result. Pi,
if you are going to round to the inch, call it 3.14. The radius
will be half the diameter...20 inches. Find a calculator and
multiply 2 X 3.14 X 20...you can do it. You can also multiply pi
times the diameter and get the same result.