If the slope of the Great Pyramid was indeed determined in this manner then the ratio of twice its base to its height would be exactly three and a seventh which is, coincidentally, not too bad an approximation to pi. That the slope can be represented by an integer ratio proves nothing, it might be as much a coincidence as the value of pi. The obvious next step is to examine the angles of some other pyramids. There is a slight problem here since one has first to find published figures and then to estimate their reliability. Only on the Great Pyramid has it been possible to determine the original slope from measurements on sample casing stones.
Many books give pyramid angles but for the most part they copy from the same earlier sources.
Where they do not disagree amongst themselves they quote values tracable, in some cases, to Petrie's original 1880 measurements. Slopes are often quoted to within seconds of arc. This precision is a spurious one produced by averaging several rougher measurements. Using the best numbers available I first tried earlier pyramids such as the northern pyramid at Dashur and the Bent Pyramid. Its setback is about 29 and a third inches for each cubit of height, not too good a fit to my theory.