Question

Explain how to justify the Cross Products Property by using the Multiplication Property of Equality.

Answer 1

The Multiplication Property of Equality states that if you multiply both sides of an equation by the same number, the sides remain equal (i.e. equality is preserved).

and

Cross Product Property states that in a proportion, product of the means is equal to the product of the extremes.

So, per the Cross Product property:
A/B = C/D

So we're trying to prove that AD=BC

You multiply both sides by B. You get AB over B which is A and CD over D. So now you have A=CB/D

Now multiply both sides by D. You get AD = CBD over D which is the same as AD = BC.


Ta-dah!