Answer:
The two interior angles plus the unknown angle add up to 180. The exterior angle plus the unknown angle also add up to 180.
So 180-(9x+1+11x-2)= 180-19x+3. 20x-1= 19x+3 so,x=4
The angle measures are 42, 37, and 101 which add up to 180.
Step-by-step explanation:
