Angle 1 is 50 degrees and angle 2 is 48 degrees. Added up, they total to 98 degrees. This is angle DEF.
Angle DEF is congruent to angle ABC because they are alternate exterior angles and because lines m and n are parallel
We are told that angle ABC is bisected (aka cut in half) because of line s; which means that the angles labeled "4" and "5" are exactly half that of angle ABC = 98 degrees
Therefore, angle 4 is 98/2 = 49 degrees and so is angle 3 (due to angles 3 and 4 being vertical angles; angle 3 = angle 4)
