Answer:
I haven't done this type of math in a while so sorry if it is wrong. The answer is 99
Explanation:
All the angles will equal up to 360 degrees.
So add all of the angles and that will give you 261. Next, minus 360 and 261. That will give you 99.
Step 1: 108+72+81=261
Step 2: 360-261=99
(sorry if im wrong).