Suppose line k has equation x=3. Compare the areas of ABCD and A’B’C’D’ = (T(1,2)° Rk) (ABCD). Suppose ABCD is a rectangle with length l and width w. It’s area is given by the expression ___. Rigid motions [sometimes, always, or never] reserve links and width, so they [never, sometimes, or always] change the value of the area. Therefore, the areas of ABCD and A’B’C’D’ [might or might not, cannot, must] be equal. Similar reasoning applies when ABCD is not a rectangle.