Putting the term 89 degrees in front of another word negates the following word. The term is the basis in which only 90 degrees is the true being of something. Anything referred to as being 89 degrees of (insert work) is therefore not the thing being referred to.
That test was 89 degrees of easy!
Her haircut is so 89 degrees of trendy.
I can't stand that bitch she's so 89 degrees of cool.