Hello!
First, find angle BOA on the protractor. To do this, look for point B, point O, and point A.
Now, we see some markings that mark what degree point B and point A are at. Point B is marked at 60 degrees, and Point A 40 degrees.
Now, all that's left to do, is subtract the two measurements.
60 degrees - 40 degrees = 20 degrees
Therefore, your answer is 20.
Hope this helps!