Answer:
a. 18 b. 119°, 118°
Explanation:
a. Given angles are vertical, so they are equal.
6a+11 = 2a+83
6a-2a = 83-11
4a = 72
a = 72/4
a = 18
b. Substituting the value of a in the given angles,
6a+11 = 6*18+11 = 108+11 = 119°
2a+83 = 2*18+83 = 36+83 = 118°