Answer:
Find the circumference,
C = 2πr
Where 'π' is pi (3.14 or 22/70, and 'r' is the radius.
To find the radius of a diameter, you must the half of the diameter:
Diameter/2 = radius
6/2 = 3 is the radius.
Plug this into our formula;
C = 2πr
C = 2 x 3.14 x 3
C = 6.28 x 3
C = 18.84 feet.