Quadrilateral [math]ABCD[/math] has the following vertices: [math]A (–4, 4)[/math], [math]B (2, 8)[/math], [math]C (3, 4)[/math], and [math]D (–3, 0)[/math]. Determine whether the quadrilateral is a parallelogram. Verify your answer using slope and distance to prove or disprove that opposite sides are parallel and opposite sides are congruent.