330°
Explanation: Given Circumference=12 units.
Arc =11units.
Angle subtended at centre=arc/radius
(this is lengthy and Involves big decimal.. So lets look at another method↓)
Again.. In a More Discrete way...
If we Divide the arc By circumference and multiply this with 360 We will get the answer.
i.e angle subtended=11×360/12=11×30=330°