Okay so we know a straight line is equal to 180 degrees, so first thing to do is subtract 180 by 116 to get angle C
C = 64
then we know all the angles in a triangle add up to 180 also
so we can do 64 + (2x + 4) + (3x - 13) = 180
combine like terms:
55 + 5x = 180
solve: x = 25
plug this back into the equation for angle A:
2(25) + 4
A = 54
