Answer:
120°
Step-by-step explanation:
[tex]m\angle A = \frac{1}{2} \{(360 - 60) \degree - 60 \degree \} \\ \\ m\angle A = \frac{1}{2} \{300 \degree - 60 \degree \} \\ \\ m\angle A = \frac{1}{2} \{240\degree\} \\ \\ m\angle A = 120 \degree [/tex]
