Answer:
[tex] m\angle R = 50 \degree[/tex]
Step-by-step explanation:
By inscribed angle theorem:
[tex]m\angle R = \frac{1}{2} [360 \degree - (120 \degree + 140 \degree)] \\ \\ m\angle R = \frac{1}{2} [360 \degree -260 \degree] \\ \\ m\angle R = \frac{1}{2} \times 100 \degree \\ \\ m\angle R = 50 \degree \\ \\ [/tex]
