Question 602569
Well, this is a rather simple problem. 
The formula for circumference of a circle (the one I use anyways) is piXd.
(d=diameter.)
So, if we use pi=3.14, then the equation for the curcumference of this circle is 3.14X11
So, multiply...and the circumference should be 34.54.
Although, don't forget, it seems in entering the problem you have forgotten units. Just know, that the circumference is in the same units as the diameter. (If diameter is 11 meters, circumference is 34.54 meters, etc.)
Hope I helped! :) 
-Rosey