The reference angle of 30 degrees is 30 degrees itself.
Reference angles are the acute angles formed by the terminal side of an angle in standard position and the x-axis. For angles measured in the first quadrant, the reference angle is simply the angle itself. Since 30 degrees is in the first quadrant, its reference angle remains unchanged.
To summarize, when you have an angle between 0 and 90 degrees, like 30 degrees, the reference angle is the angle itself.