Answer :
m< 18 = 139° ( vertical angles)
m<17 = 180° - 139° = 41° (angle on a straight line)
m<15 = 41° (vertical angles)
m<5 = m<15 = 41° (vertical interior angle)
m<7 + m<6 + m<5 = 180° (angle on a straight line
47° + m<6 + 41° = 180°
m<6 = 180° - 47° - 41° = 92°
m<12 + m<6 + m<15 = 180° (sum of interior angle of a triangle)
m<12 + 92° + 41° = 180°
m<12 = 180° - 92° - 41° = 47°
m<12 + m<11 + m<10 -