The best planarity data for the Great Pyramid of Giza's granite coffer still comes from Flinders Petrie's late-1800s survey. He set measurement points 6 inches apart, recorded how far each stone face deviated from reference planes, and checked wall thickness with calipers. The west wall came out about 5.9 inches thick at both ends but only 5.64 inches at the centre, and the east wall grew from ~5.75 inches at the south end to ~5.97 inches at the north end. Corner angles read 89°47′ at the northeast and southwest, and 90°13′ at the northwest and southeast — a matching pair that implies a slight parallelogram skew rather than a true rectangle. 🪨📐
Petrie's coffer survey shows Great Pyramid sarcophagus skewed 13 arc minutes
EgyptGeneral
Key facts
- The most recent planarity data for the Great Pyramid's granite coffer comes from Flinders Petrie's survey in the late 1800s
- Petrie set out a network of measurement points spaced 6 inches apart, measured deviations of the stone surfaces from reference planes, and independently checked wall thickness with calipers
- He organised the data around two sets of parallel reference planes: the inside and outside faces of the east and west walls, and of the north and south walls
- The west wall measured about 5.9 inches thick near either end but narrowed to 5.64 inches at its centre, a difference of roughly one third of an inch
- The east wall gradually increased in thickness from about 5.75 inches at its southern end to 5.97 inches at its northern end
- Corner angles were measured at 89 degrees 47 arc minutes for the northeast and southwest corners and 90 degrees 13 arc minutes for the northwest and southeast corners
- The matching opposite-corner values indicate a slight parallelogram skew of 13 arc minutes rather than a perfect rectangle, while the walls remained approximately parallel overall
Was this story useful?
Keep exploring
Every site on this page sits on the globe, and the people who research them are on the Discord.
3D Globe · Sites by country · Story Archive · Research Library · Weekly Journal · Search
AI-generated text · images from the original sources · always verify with the sources.