If 2 supplements 3, then does 1 supplement 4?

Question

The figure shows that there are two parallel lines, lines a and b. There is a transversal line called line t. No angles are 90 degrees and the parallel are vertical. Based off of the consecutive interior angles theorem, angle 2 supplements angle 3. It kind of looks like this (note, line t is slanted and is not perpendicular):

a b

1 l 2 3 l 4

--l------------------------------l---------- t

8 l 7 6 l 5

Answer 1

You are correct, 1 would supplement 4. This is because angles 1 and 3 are equal due to them being corresponding angles. By the same logic, 2 and 4 are corresponding angles and therefore equal. Thus since 1+2 = 180, 1+4 = 180

Answer 2

Yes. If m // n, then all red angles are equal, all blue angles are equal, and all combinations of red and blue are supplementary.