"if parallel lines have a transversal, then corresponding angles are congruent." on the fence, lines a and b are parallel and line c is a transversal. how many pairs of corresponding angles are available on the picture to use to prove the theorem? which given pair of angles can be used? a) 2 pairs; ∠5 and ∠1; b) 2 pairs; ∠5 and ∠7; c) 4 pairs; ∠2 and ∠4 d) 4 pairs; ∠3 and ∠5;