_______pairs of corresponding angles formed by a transversal of two parallel lines.

Eight angles are formed when a transversal intersects two parallel lines. The eight angles will form four pairs of corresponding angles when combined.

i.e. the corresponding angles will be:

$\angle 1 = \angle 5 , \angle 2 = \angle 6 , \angle 3 = \angle 7 , \angle 4 = \angle 8$