The quadrilaterals have different orientation and location. In ABCD, vertex C is the bottom right vertex. In A′B′C′D′, the corresponding vertex C′, is the top left vertex. To line up their orientations, we can rotate ABCD about the origin 180∘.
Therefore, by only one transformation, we can map ABCD onto A′B′C′D′. Rotation: 180∘ rotation about the origin