Pyramid Diagram

No structure in the world has undergone nearly as much scrutiny and careful (or careless!) observation as the Great Pyramid of King Khufu ("Cheops" in Greek) built c. 2500 B.C.

In 1881, archaeologist Flinders Petrie surveyed the entire pyramid. However, due to the changing courses of sand outside the pyramid, his internal pyramid measures are the only ones used today. For base measures, most people use the findings of J. H. Cole's 1925 survey.

Cole found that the pyramid base measured on average 230.363 x 230.363m. And Petrie found that the King's Chamber measured (L x W x H) 10.47 x 5.24 x 5.86m. The dimensions of the King's Chamber are very reliable since they are so well-preserved.

It is easy to convert from meters to Royal Cubits; the problem lies in what measures one assumes were then standard. Petrie found that 1 Royal Cubit= 52.405cm; the pyramid-base suggests 1 Royal Cubit= 52.35cm; and the King's Chamber suggests 1 Royal Cubit= 52.35cm. This is why the base measures 440 x 440 Royal Cubits, and the King's Chamber 20 x 10 x 11.18 Royal Cubits (the chamber height is unusual since it is half the floor-diagonal).

Calculating the height of the pyramid is problematic since the capstone no longer exists. According to ancient writers, it stood 280 Royal Cubits high. As for the apothem, again sources vary but it was likely either 352 or 356 RC. It really depends on the length of the cubit one assumes.

But since the pyramid height and base meet at right angles, one can use the Pythagorean theorem to solve for the apothem. With a height of 280 and a base of 440, the apothem is 356 Royal Cubits. But ancient Greek writers also stated that the apothem was 400 Greek cubits. For this to be true, the apothem was 352 Royal Cubits.

Interestingly, the King's Chamber diagonals form a Pythagorean 3:4:5 triangle (15:20:25 Royal Cubits).

Petrie also found that the King's Coffer exterior measured 2.28 x 0.97 x 1.05 m, while its interior measured 1.97 x 0.67 x 0.87 m. No elegant Egyptian measures have ever been discovered for these.

In general, the full implication of these plans and measures will become more apparent in subsequent sections, particularly in the Greek context.

For now, one of the more compelling observations is that the base of the pyramid squares its height. This means that the total perimeter around the base of the pyramid is the same as the perimeter of a circle drawn around its height. In this way, Egypt enthusiasts' believe the Great Pyramid "squares the circle"