1. vertical angles are congruent....so < n = 90
25 + 90 + 40 + m = 180
155 + m = 180
m = 180 - 155
m = 25
so < n = 90 and < m = 25
2. 50 + 90 + n = 180
140 + n = 180
n = 180 - 140
n = 40
50 + 90 + m = 180
140 + m = 180
m = 180 - 140
m = 40
so < m and < n = 40
3. 50 + 40 + 52 + m = 180
142 + m = 180
m = 180 - 142
m = 38
40 + 52 + 38 + n = 180
130 + n = 180
n = 180 - 130
n = 50
so < m = 38 and < n = 50
