8. Let ABCD be a parallelogram with A on top left, B on top right, D on bottom left and C on the bottom right. Prove that opposite sides of a parallelogram are congruent.

Step-by-step explanation:

A parallelogram is a quadrilateral with four sides.

Given parallelogram ABCD, to prove that opposite sides of the parallelogram are congruent.

Join D to B, the diagonal of the parallelogram which is also a traversal.

So that;

    <ABD = <BDC (alternate angle property)

    <BAC = <ACD (alternate angle property)

Also, diagonals;

      /AC/ = /BD/ (reflexive property)

Then;

      ΔABD = ΔCBD (Angle-Side-Angle, ASA, property)

Thus;

     /AB/ ≅ /CD/ (corresponding sides of congruent triangles are congruent)

    /BC/ ≅ /AD/  (corresponding sides of congruent triangles are congruent)

Therefore, the opposite sides of the parallelogram ABCD are congruent.

i hope this is what you were looking for.

see attached graph