Answer:
∠ QPR = 90°
Step-by-step explanation:
The exterior angle of a triangle is equal to the sum of the 2 opposite interior angles.
120° is an exterior angle of the triangle , then
∠ QPR + ∠ PQR = 120° , that is
∠ QPR + 30° = 120° ( subtract 30° from both sides )
∠ QPR = 90°
