My reasoning is I went from one angle to another by subtracting 180 from my answers. For example angle 132 is supplementary to the missing angle next to it. I subtract 180 from 132 and get 48. That already solves the 2 equivalent angles in the triangle so I have 48+48+x = 180 because a full triangle equals 180. I get x = 84 then I do the same thing I did with angle 132. Angle 84 is supplementary to the missing angle next to it. I subtract 84 from 180 and get 96 then go diagonal from angle C (which is 96) to angle A. Those are supplementary so I subtract 96 from 180 and get 84.