Please help question in picture

Step-by-step explanation:

Scince 3 and 4 are forming a straight angle together which we knew it's equal to 180°

m<3 + m<4 = 180°

m<3 = 180°- m<4

m<3= 180°- 81=99°

The sum of triangle angle = 180

m<1 + m<2 + m<3 =180°

42° + m<2 + 99° = 180°

m<2 = 180° - 99° - 42°

m<2= 39°

f is the midpoint of