Quadrilateral $ABCD$ has vertices $A\left(0,\ 3\right),\ B\left(0,\ 6\right),\ C\left(4,\ 6\right)$ , and $D\left(4,\ 3\right)$ . Vertex $D$ is translated 2 units right and the other vertices do not change position. How much greater is the area of quadrilateral $ABCD'$ than the area of quadrilateral $ABCD$ ? The area is greater by square units.