Answer:
180
Step-by-step explanation:
You know that the angle at the top is 31 degrees. A right angle is 90 (B) degrees. 90 - 31 = 59. So the un-named part of the top angle is 59 degrees. This also means the bottom angle to the right is 31 degree. (It is opposite for each side. 31 on the other triangle and 59 on the one we're working with.) Angle B is a right angle which is 90 degrees.
So far:
A: 59
B: 90
C: 31
59 + 90 + 31 = 180!!!
