The coordinates of the vertices for the figure HIJK are H(0, 5), I(3, 3), J(4, –1), and K(1, 1). To determine if it is a parallelogram, use the converse of the parallelogram diagonal theorem. This states that if the diagonals, then the quadrilateral is a parallelogram. The midpoint of HJ is and the midpoint of IK is (2, 2). Therefore, HIJK is a parallelogram because of the diagonals, which means they bisect each other.