Make sure the post is 'square' to the floor. [=make sure that there is a right angle where the post and the floor meet]
I'll go on the trip if I can 'square it with' my parents. [=if my parents will agree to let me go]
Here's the rest of the money. Now we're 'square'. [=now we don't owe each other anything]
(..) No, I'm on a special diet. You gotta give me some answers. Yes, no. To get to the other side. I don't want to know what the square root of pi is. You knew that? How did you know where I was? I didn't. - All right. - What? (..)2008 Twilight