Angles like y and x on number one are equal. And since the two lines are parallel, the angle that is equal to 50 degrees is congruent to angle y. On the second one the angle of 40 degrees and angle m are equal. So all you have to do is subtract 40 from 180. On the third one, angle a and b are equal and the angle of 125 is equal to a. I hope you catch the pattern .
