x=21°
y=31.5°
Explanation:
Since it is a whole circle (360°) and there are 40 section (90° each).
2 of the 90° +(180°)are clearly stated there so you do:
360°-180°=180°
1. On the side that have 2 'y's you do:
90°-(12+15)=63
Then 63/2=31.5°
Therefore y=31.5°
2. On the side with 3 'x's you do:
90°-(12+15)=63
Then 63/3=21°
Therefore x=21°
To cross check you do:
90+90+15+12+21+21+21+15+12+31.5+31.5=360
I hope you find this helpful.