URGET: Inscribed Angles
Find the measure of angle R.

Answer:
∠ R = 50°
Step-by-step explanation:
The inscribed angle R is half the measure of its intercepted arc QS
QS = 360° - (120 + 140)° = 360° - 260° = 100° , then
∠ R = 0.5 × 100° = 50°