Quadrilateral ABCD is a parallelogram if m∠A + m∠B = 180°, m∠B + m∠C = 180°, m∠C + m∠D =180°, and m∠D + m∠A = 180°.
I am doing a geometry unit, and I really need to construct a diagram of a shape, a quadrilateral I think (sance it is listed their above).
