fmetrol: "Petrie wrong?"

DJ: "On base and height measurements."



The original height of Khufu's pyramid can only be estimated mathematically by determining the mean length of the original line of the four base sides, the angle of incline of the core masonry at the corner edges, or the angle of incline of the face of the remaining in-situ casing stones.

According to J.H. Cole's 1925 survey, the mean length of a base side was 230.364 m (compared to Petrie's 230.347 m, which is only a very small, 1.7cm (0.7") difference, so they are both more or less in agreement)

Cole's 230.364m divided by 440 = 0.5236m, which means the length of the cubit used in the design was to the nearest mm, 524mm long. This is confirmed by Petrie's estimate for the 524mm length of the cubit obtained from the length / width of the sarcophagus chamber (20 x 10 cubits). This was not the only structure where 440 cubits was used - the specified width of Izezi's Dyn 5 Sed festival enclosure was also 440 cubits.


An in-situ casing stone uncovered in 1837, was measured by Mr. Brettell, a civil engineer working for Vyse. (when Perring left Giza he covered the casing stone, but it was soon discovered, broken up and taken away by the locals). The 51.866 deg angle of incline for the face of this casing stone is virtually identical to a sqd 5 1/2 (7 : 5.5) defined slope of 51.843 degs.

Petrie's weighted mean for the north face of the pyramid was 51.844 degs which again, is virtually identical to sqd 5 1/2.


In 1866, astronomer C.P. Smyth measured the angle of the arris corners of the core masonry with "a powerful astronomical circle and telescope" and obtained a figure of 41.995 degs. A pyramid with an arris corner of 41.995 degs, has a height equal to the radius of a circle with a circumference equal to the perimeter of the square base of the pyramid. C.P. Smyth was hoping to confirm this relationship, so he may have just seen what he wished to see.

However, the arris corner of a sqd 5 1/2 defined pyramid is 41. 986 degs, which is virtually identical to Smyth's measured angle of 41.995 degs, which means his measurement was accurate after all.

Based on the survey data, Khufu's pyramid was designed using an approx. 524 mm long cubit, and the length of a base side was 440 cubits. Although we have no contemporary textual evidence to confirm this, its also highly probable that sqd 5 1/2 defined the angle of incline of the faces, which means the height was originally 280 cubits.

CT