When it comes to diameters, perimeters and volumes the suggestive 256/81 is all we have to fall back on. There is no textual evidence for anything else including 22/7.

Circular maths probably came into being during the building of early-dynastic grain silos but it debatable if they were interested in perimeters. They would however have been interested in widths (diameters).

In MMP 10 they went from diameters to areas.

As for the cubit rod being used to express Pi as 22/7 ..... well it breaks me up. It's just nonsense.

All the concentric circle crap we see being posted for Giza is also nonsense.

Exact arcs laid out with ropes I suppose. Did I mention that I know someone who has actually carried out extensive trials. what they found was two fold - first that ropes stretch and sag. Secondly that a large circle, if walked along the perimeter, could be divided by the distance across to get a reasonable approximation for the number we know as Pi.

Graham.