→We are given an exterior angle (outside of the triangle) as (x + 72). We are also given two interior angles as 34 and 90. The sum of the two farthest interior angles away from the exterior, is equal to the exterior. So this means that ∠R(90°) + ∠S(34°) = ∠PQS(x + 72), and we can set up the equation like that:
