when you want to divide by a fraction (n/d), flip the numbers and make multiply sign, but make sure always flip the second number (the number after the divide sign) and not the first and change the divide to multiply
The answer is; "Quadrilateral ABCD is congruent to quadrilateral A′B′C′D′ because you can map quadrilateral ABCD to quadrilateral A′B′C′D′ using a translation 7 units to the right, which is a rigid motion."