It's not just about your HS GPA. They also consider your extracurricular activities, things you do where you have been able to show leadership qualities (ie. captain of your basketball team). They also look at your volunteer work and quality of character. Think of it as this: you are applying for a job that thousands of others are applying to as well. What will put your application above the others?
A hermit who has a 97% average, plays no sports after school and all around keeps to himself may show that he is insanely book smart but has little social experience or leadership potential. His application could be below a kid who has an 86% average, captain of his hockey team 5 years in a row, is a candystriper at the hospital, and has his First Aid, soccer refereeing, and any other courses you can pick up as a minor.
I know it doesn't answer your question stright-up, but it isn't one you can give a uni-dimentional answer to either.