"I see your hat between the dresses."
Translation:Vedo il tuo cappello fra i vestiti.
It seems as though the difference is purely for euphonic (pleasing phonetic) reasons... However it seems that "tra" is the most commonly used form. See here: http://italian.about.com/od/grammar/a/italian-preposition-tra.htm
I am no expert, and just learning the language myself, but found that article and it did illuminate the subject for me. Hope it helps. Cheers!
From the 'possessives' lesson, it seems to be most common when talking about your hat, his hat, my hat etc. that it is il <appropriate possessive> cappello. The 'the' pretty much always appears though it might sometimes be hidden in one of the combined bits so sul mio cappello 'on my hat' because sul is 'su+il'
Hi Michael, as cput88 said, this is actually a spelling mistake for "cappello", rather than "tra" being wrong....I did the exact same thing :(
EDIT: Oh, and apparently it wants "fra" as well....from a quick google search, apparently "tra" applies more so when it's between two things, rather than between many things (in this case, the dresses, of which we can suppose that there are many).