Question

Let ABCD be a quadrilateral in which ∠A = ∠C, and ∠B = ∠D. Prove that ABCD is a parallelogram.

Answer 1

Given: ABCD is a quadrilateral, where .

To Prove: Quadrilateral ABCD is a parallelogram.

Proof:

Similarly,

Hence, quadrilateral ABCD is a parallelogram.