The formula to find the circumference is pi*radius^2. Since your radius is 6371, the radius squared is 40589641 and that times pi is 127451473. That is your circumference
In order to find the circumference of a circle, you must use the formula c=2**r.
Since you're already given the radius, all you have to do is use the formula and do 2 times 3.14 times 6371 and you get 40009.88 as your circumference.
