Theorem: If two opposite sides of a quadrilateral are congruent and parallel, it is a parallelogram
Given: In a quadrilateral ABCD,AB‾≅CD‾\overline{AB}\cong\overline{CD}AB≅CD and AB‾∣∣CD‾\overline{AB}||\overline{CD}AB∣∣CD
To Prove: Quadrilateral ABCD is ∣∣m||^m∣∣m
Construction: Join B and D.
Proof:
