First, I will find angle 2
115° + m< 2 = 180° (angle on a straight line)
subtract 115° from both-side of the equation
m<2 = 180° - 115° = 65°
m<2 = 65°
m<1 + m<2 + 80° = 180° (sum of angle in a triangle)
m<1 + 65° + 80° = 180°
m< 1 + 145° = 180°
subtract 145° from both-side of the equation
m<1 = 180° - 145°
m<1 = 35°
m<2 + m<4 = 180° (angle on a straight line)
65° + m<4 = 180°
subtract 65 from both-side of the equation
m<4 = 180° - 65°
m<4 = 115°