Answer:
y=66
Explanation:
Start with the angle that has the purple arrow pointing to it. Next to it, part of the right angle is 27 degrees so you subtract that from 90 degrees, which makes you get 63 degrees. The measurement of all a triangle's angles is 180 degrees, so you add 63 and 51 to get 114, then subtract 114 from 180 to get 66 degrees.
Hope this helps!