Question 395990
Eh, the only way is to do a bunch of angle chasing. For example, since c || d and d is perpendicular to e, then c is also perpendicular to e, and angle 4 = 30 degrees.


Just use the facts that supplementary angles add up to 180, that opposite angles (e.g. angles 10 and 11) are congruent, and that the sum of the angles in a triangle add to 180 degrees.