If a dress that is made out of 2 yards of fabric will shorten 2 inches because of the hem, how much would a dress made out of 1.5 yard of fabric shorten because of the hem?

1.5/2 * 2 = 1.5 in

assuming that hem size is proportional to dress size. Somehow I doubt that. I'd imagine the hem is a constant width. But, for the topic at hand, I guess we need the proportion.