The Egyptian pyramid
Mastaba, step, bent and true pyramids; the slope of a true pyramid set by its seked, the run in palms for one cubit of rise.
The rules it illustrates
The seked of a pyramid. Specify the slope of a pyramid face by its seked: the number of palms (and fingers) by which the face runs inward for every cubit of rise. The height follows from half the base divided by the seked, times seven.
The Great Pyramid: 440 cubits by 280. The Great Pyramid of Khufu was laid out 440 royal cubits square and 280 cubits high, a seked of exactly 5½ palms and a slope of about 51°50′.
Measure in cubits, palms and fingers. Lay out Egyptian buildings in royal cubits (≈ 52.4 cm) of seven palms of four fingers, so that every dimension and every slope can be stated in whole or simple fractional units.
From mastaba to true pyramid. The royal tomb grew in about a century from a low battered mastaba, through a stack of diminishing mastabas (the step pyramid), to a smooth-faced true pyramid; a failure of stability in between forced the change of slope of the Bent Pyramid.
The bent pyramid: changing the seked in mid-course. When a steep pyramid shows signs of distress, flatten the slope of the upper part: Sneferu’s pyramid at Dahshur rises at about 54° for its lower part and about 43° above.
Where it appears in the book
In the styles Ancient Egyptian.
In the chapters The Ancient World.