Question

What statement is used to prove quadrilateral ABCD is a parallelogram

Answer 1

The correct answer is the second choice:

<BCD + <CDA = 180

This fact implies BC and AD are parallel which is the essential property of a parallelogram.

Answer 2

I believe D is the answer. (Triangles BPA and DPC are congruent.)

Angles BAD and ADC are not congruent.

Sides CD and DA are also not congruent