Question

given: abcd is a parallelogram. prove: ∠a and ∠d are supplementary. by the definition of a parallelogram, ab∥dc. ad is a transversal between these sides, so ∠a and ∠d are same - side interior angles. because ab and dc are parallel, the same - side interior angles must be by the same - side interior angles e, ∠a and ∠d are supplementary. complementary congruent corresponding supplementary

Explanation:

When two parallel lines (AB and DC in the parallelogram) are cut by a transversal (AD), same - side interior angles are supplementary according to angle - pair relationships in parallel lines. Since ∠A and ∠D are same - side interior angles formed by parallel lines AB and DC with transversal AD, they are supplementary.

Answer:

supplementary