Question

If two lines re-intersectsd by a transversal line if any pair of bisectors of their alternate intrrior angle is parallel then prove that two line are parallel.

Answer 1

let l,m be lines. from triangle ABC and ACD. side a is common, side b,e are parallel and the side lengths of c,d are same as e,b are parallel.
hence triangle ABC is similar to triangle ACD. so side c is parallel to side d.