Final answer:
The reference angle of 50 degrees is 10 degrees.
Step-by-step explanation:
A reference angle is the acute angle formed between the terminal side of an angle and the x-axis in standard position. To find the reference angle, we subtract 90 degrees or a multiple of 90 degrees from the given angle until we obtain an angle between 0 and 90 degrees.
In this case, the reference angle of 50 degrees is found by subtracting 40 degrees from 50 degrees. So, the reference angle of 50 degrees is 10 degrees.
Therefore, none of the angles provided have a reference angle of 50 degrees.