Find the value 'x' in this given picture

Hi.
This is just messing around with exterior angles.
I say around 120 degrees, if I forgot what exterior angles were.
But with quick calculation, it is probably 120 degrees

Sum of all exterior angles = 360°

Given that it is a regular octagon, 
one angle = 360 ÷ 8 = 45°

Given that the other is a equilateral triangle ( all angles being 60° each)
x = 45 + 180 - 60 = 165°


x = 165°

Answer d; a supplementary angle = 180°, so if that angle = 150°, y would = 30°.