3D trigonometry, part c, please explain how to find the answer

Which statement explains how you could use coordinate geometry to prove that quadrilateral abcd is a parallelogram? -5 -4 -3 -2 -1 t 1 2 3 4 prove that all sides are congruent and have slopes that are opposite reciprocals prove that segments ad and ab are congruent and parallel prove that opposite sides are congruent and have equal slopes prove that segments bc and cd are congruent and parallel

Figure abcd is a parallelogram. if point c lies on the line x = 2, what is the y-value of point c?

Tell whether the two rates form a proportion