You will never ever be able to explain the exact center positions of the two largest pyramids with geometry. The outer edges of the pyramids, yes, but the centers no. You may think youdid at some time but if you make an exact CAD drawing of Petrie's survey data you will always find a flaw. That's because the center positions are not based on any geometry. They are based on something natural and random, star positions (in my opinion). There may be some geometry between either of the two large pyramid centers and the 3rd pyramid center but not the centers of the first two with each other. I tried everything imaginable and it never ever works out perfectly. I mean, it's conceivable but I personally don't believe it can be done.