The answer is 97, because when you add up 42 and 55 you get 97. Then you subtract that by 180 because a triangles angles add up to 180. 180-97=83. Z=83. Z and y are supplementary to eachother, so therefore 180-83= 97. Supplementary means they add up to 180.
Do you mean checking your work? In that case it would be 9*20.
Oh wait a minute i have to write this down
Answer:
8/15
Step-by-step explanation: