If the radius of a circle was 3 inches, what would the circumference be?

Circumference=2$${\mathtt{\pi}}$$r, r for radius.

Plug in the values.

Circumference = 2 x pi x radius

                    C  =  2 x pi x 3  =  18.85 inches (approximately)

I like the answers that you are giving DarkBlaze347.  Askers should do some work for themselves :)