Answer:
 ? = 109 degrees 
Explanation:
45 + 75 + _ = 180 ( look for vertical angles)
45 + 75 + 60 = 180 
 60 +79 + _ = 180 (look for a straight line that forms 180 degrees)
60 + 79 + 41 = 180 
68 + 41 + _ = 180 (look for a triangle that adds up to 180)
68 + 41 + 71 =180
180 - 71 = 109 (look for a linear pair)