Answer: 34
Explanation:
m3 + m2 = 180
m2 + m1 = 180
so
m3 = 34
34 + m2 = 180
m2 = 146
146 + m1 = 180
m1 = 34
There is another rule which I cannot remember, yet it is much more simple, and don't know how to explain, so here's this one.
1.6m questions
2.0m answers