Ogygos: OK I did the math like in your presentation. I created a square at Menkaure's end.
SC: Menkaure's pyramid (G3) is not square but very slightly rectangular (resulting from the 95 degree L2 line). If G3 was a square then this angle of L2 would have to be 90 degrees and the mirrored G3 base would also be a square resulting in G2 and G1 being the same size. They are not the same size by virtue of G3 (and its mirrored G3) being very slightly rectangular. Keep in mind also that the west and north elevations of G3 are defined by the square on the diagonal (L2) but that the south and east elevations of G3 seem to have been defined by alignment to the cardinal directions.
EDIT: Fix Typo.
Post Edited (07-Feb-12 00:03)