Answer:
79
Explanation:
Sense all the lines are straight, and will never cross, then adjacent angles must always add up to 180 degrees. 3 and 4 are adjacent. Thus they must add up to 180. So set up as 101 + x = 180. x=180 - 101, and find that x = 79. Plug x back into check. 101 + 79 = 180. and 180= 180. The answer is 79 degrees.