1. You can find angle “b” due to it being vertically opposite of the 52 degrees. This makes angle “b” also 52 degrees.

2. Angle “c” can be found due to the rule of it being a corresponding angle to angle “b”. This makes angle “c” 52 degrees as well as angle “b”. Angle “a” is also vertically opposite to the corresponding angle also making it 52 degrees.

3. The remaining angle can be found due to a rule involving the sum of the anger in a triangle. There are 180 degrees in a triangle and when you subtract 180 – Known angles you get the final angle. Since we know angle “c” = 52 degrees, and the unnamed side is corresponding to the 73 degrees we just have to input the numbers. 180 – 52 – 73 = 55 degrees. This makes angle “d” 55 degrees.