Answer:
50
Explanation:
120 +angle1 = 180 angle 1 is 60 70+60+angle2 should be equals 180 so 2 is 50 degree
1 is 60 degree 3 is 80 degree 4 is 100 degree 2 is 50 degree
60+40 +angle3 = 180 angle3 is 80
3+4 should be equal 180 3 is 80 180-80= 100 4 is 100