Question

PLEASE SOMEONE HELP.... fan and medal
Parallelogram ABCD contains two congruent triangles. In two or more complete sentences, use the triangles to prove opposite sides are congruent in parallelogram ABCD.

Answer 1

Since ABCD is a parallelogram, opposite sides are parallel by definition.
AD is parallel to BC and AC is a tranversal.
Angles DAC and BCA are congruent because they are alternate interior angles.
Sides AB and DC are parallel and AC is a transversal.
Angles DCA and BAC are congruent bec of alt int angles.
AC is congruent to AC.
Triangles DCA and BAC are congruent by ASA.
AD is congruent to BC by CPCTC.
DC is congruent to BA by CPCTC.