The 90/10 rule in financial aid is a rule enacted to keep for-profit trade or technical schools from recruiting only low income students or students who aren't likely to do well but qualify for financial aid. This rules requires schools to show that 10% of their income comes from sources other than federal financial aid, which some schools interpret to mean students have to provide 10% of their costs. This, and other laws pertaining to these schools, are being examined for their fairness.
In the meantime, for you, this means that you won't be offered federal loans to cover the 10%. You need to either pay it out of pocket, borrow it from someone and pay them back, get a private scholarship, or take out a private loan. You can also see if your employer or your parents employers have a program to help with post-secondary ed costs. Your school's financial aid office may be able to help, or they may not. Fastweb.com may have some helpful scholarship info.