
Samuel P. answered 06/20/20
Former high school math teacher. Currently working in finance at Big 4
Given: AB is parallel to DE and AD bisects BE.
Prove: Triangle ABC is congruent triangle DEC.
BC is congruent to EC by definition of bisect.
<ABE is congruent to <BED by alternate interior angles.
<ACB is congruent to <ECD by vertical angle theorem.
Triangle ABC is congruent to triangle DEC by ASA congruence theorem (or postulate depending on how the topic is presented).