Given: Quadrilateral ABCD is a parallelogram Prove: Triangle ABC is congruent to Triangle CDA

Answer 1

Based on the name of the parallelogram ABCD and the definition of a parallelogram, sides AB and CD are congruent and sides AD and BC are congruent. Since the diagonal AC is the same for triangles ABC and CDA, we can use the SSS theorem to prove that triangle ABC is congruent to triangle CDA (side AB ≅ side CD, side AD ≅ side BC, and side AC ≅ side AC).