Well.
The relation between the circumference of a circle and its diameter is described by the following equation: [tex] Thecircumference=\pi d[/tex]
where d is the diameter of the circle.
For a giving diameter (d=3ft), we can substitute in the previous equation
The circumference of a circule= 3.14*3 (you can use ur calculator to find the exact number i guess it will be about 9.42 ft)
I hope it helps.