The equation to solve for angle 1 is reliant upon the fact that the measure of an exterior angle is equal to the sum of its interior angles. In our case, angle 1 = 38 + 70 which is 108. Now to find angle 2 we have to rely upon the fact that angles 1 and 2 are supplementary, or angle 2 = 180 - angle 1. We have angle 1 is 108 so angle 2 = 180 - 108 and angle 2 = 72
