I can't show you how to this geometrically but you'll have to
- Use "protractor" which looks like the letter "D" laying down to measure angle x (Refer to the image I attached). When I measure from the screen, the angle is approximately 32°
- Then if we subtract value of x from 360° we can find angle y
Suppose value of x is 32°, then
y = 360° - x
= 360° - 32°
y = 328°