i don't get this

angle x = 66 degrees

180-105 = 75

I am not sure if that green angle is 39 or 30. I will assume 30

180-30-75=75

x is vertically opposite the angle that I found so it is 75 degrees too.

I magnified the image size on my monitor, and, although the larger the size, the less the resolution, I'm pretty sure that the green angle is 39^o so, Guest OP, if you know that the angle actually is 39^o simply substitute 39 for the 30 in Melody's subtraction. 

_.