Help me please I am confused what to do next

Answer:
No.8
m<1 = 74°( just like example)
m<2 = 180°-74°=106°
m<3 = 74°( just like example)
m<4 = 180°-74°=106°
(n<5) m<5 = 74°( just like example)
(n<6) m<6 = 180°-74°=106°
(n<7) m<7 = 74°( just like example)
(n<8) m<8 = 180°-74°=106°