Question 162606
In your own words, explain in detail why we can determine  which of two fractions is greater by using the cross-multiplying method. What is the rationale behind this method? What are we really doing when we cross-multiply in order to compare fractions?
----------------------------------
Typical Proportion: a/b = c/d
----------
Multiply both sides by bd to get:

(bd)(a/b) = (bd)(c/d)
---------------------------

Cancel where you can to get:
ad = bc (This is the cross-multiplication pattern)
===============
Cheers,
Stan H.