The Pyramid Inch is a unit of measurement slightly larger than a standard inch (1.0010846752 British inches or 25.4mm), and is based on the Royal Cubit, found throughout the pyramids in Egypt. This Royal Cubit is slightly longer than 25 standard inches (between 523 mm and 526 mm). Since this length was discovered in many places around the Pyramids, which are obviously works of great skill, it was assumed by some that this Royal Cubit is the natural unit of measurement for length. The Pyramid foot was also used, which is 307.15mm, which is very close to 1/100 if an arc second.

After the discovery of this, it was found that the polar radius of Earth is approximately 250 million times the length of the Pyramid inch. Proof indeed! As we have refined the estimate of the polar radius, so have people refined the length of the Pyramid inch, so that correlation is always accurate.

The sides of the Great Pyramid are approximately 365.25 Royal Cubits, and the perimeter is 36525 Pyramid Inches. A number which should be familiar to everybody. Some people take this to be another sign of the advanced nature of Ancient Egypt, others (like myself) wonder why a burial chamber would need to be in proportion to both the polar radius of Earth and to the length of the year. The pyramid inch is just another of the many mysteries surrounding the pyramids.

From my own knowledge with figures from and which I was directed to by yuo