Okay, so all you need to do is to find the missing angle.
First, remember that all the angles of a triangle equal 180°. So if you know two of the angles, all you have to do is add them, then subtract the sum from 180.
1. 78 + 37 = 115 180 - 115 = 65 Do the same thing for each triangle and your answers are.
1. 65° 2. 34° 3. 67° 4. 58°