Can you explain how you got the answer too because I don’t understand

Answer:
60
Step-by-step explanation:
The whole thing is 180 so if you subtract 180 from 120 you get 60.
Answer:
60 degrees since a straight line is 180 degrees
Step-by-step explanation:
Since part of it is 120 degrees the other part must be 60 because 120 + 60 = 180