The equation for the circumference of a circle is pi times diameter. The diameter in this case is 11. So the answer is 11 times pi or, as a decimal, approximately 34.56.
the formula for circumference is C = π×diameter, so you multiply π times 11 (the diameter) and you get the circumference, round it to the nearest tenth or hundredth if needed.
A square root can only use positive numbers, otherwise it becomes imaginary. A function needs to be real to output real values. Therefore, the domain is everything from 0 onwards.
