Step-by-step explanation:
when 2 lines cross, the angles on one side of one of these lines are mirrored to the other side.
and crossing a second, parallel line creates exactly the same angles there too, because crossing the second line is like crossing the first line. otherwise the 2 lines are not parallel. the second line is just a shifted version of the first line (and vice versa). all the other attributes are the same.
and all angles around a single point on one side of a line are together 180°.
because of all that,
angle 2 = angle 3 = angle 6 = angle 7 = 76°
angle 1 = angle 4 = angle 5 = angle 8 = 180-76 = 104°
