Unfortunately if you want a straight edge on the other edged you have to cut off the points, It isn't as painful as I thought, I didn't on this one but depending on how much time I have I have cut them off, they are only little pieces, and I imagine if you have saved all of your scraps I imagine that they are a lot less that you usually have, at least that is my experience with it,
So line up your ruler to the inside points and cut away.