Answer: B) 90
Since c is perpendicular to b (given) and line 'a' is parallel to line c (also given), this means line 'a' is perpendicular to line b.
Put another way, angles 5, 6, 7, 8 are all 90 degrees (since c is perpendicular to b). If a || c, then angles 2 and 6 are corresponding angles that are congruent.
So this is why angle 2 is also 90 degrees.
