The correct answer is letter B
h = 
multiply both sides by 2 to eliminate the fraction
2A = ( b + c)h
isolate h by dividing both sides by (b + c)
h = 
So, for each one you are trying to complete a full rotation or 360°. This means that you should add up all of the numbers and subtract that from 360.
#1. 360-279=81°
#2. 360-281=79°
7’7 cuz that would be cool