Answer :
If you have the radius, then do Radius times 2 to get the diameter, then do diameter times Pi (3.14) to get the circumference
E.g. If the radius was 4, times by 2 to get the diameter so 4x2=8 then do 8x3.14 (pi) to get the circumference.
E.g. If the radius was 4, times by 2 to get the diameter so 4x2=8 then do 8x3.14 (pi) to get the circumference.