The reference angle is the smallest angle measured from the terminal side of the angle (where the angle ends) to the x axis. The reference angle is an acute angle (i.e less than 90° or π/2)
For O = 11π/6 = 1.833π
1.833π is in the fourth quadrant between 3π/2 radians and 2π radians. Since it is in the fourth quadrant, the reference angle is given as:
