Style fixes to Triangle facts

This is really awkward logic, and I don't think refactoring will do much here.  It will still be 3 lines and essentially a case statement.  The way a, b, and c are used in the acos argument doesn't lend itself well to refactoring.  I don't see how it will help much to do it.  Also, part of the problem is I have no idea what this logic means and frankly I'm not going to spend a bunch of time figuring that out because that's not my purpose here :).  Let me know if you have any ideas.