# Geometry 1: π ###### understanding the megalithic: circular structures: part 1

It would require 3 and a bit diameters to wrap around the circle – the ratio of 3 and a bit diameters to the perimeter is known as “Pi”, notated by the Greek symbol “π”. Half of the diameter, from the circle’s center to its edge, is named its radius.

A circle is made using a staked rope whose other end can only then move in a circle of radius equal to the rope’s length. That is, if you can make a wooden stake and weave a rope out of fibres, you can make circles. You can then create an encircling fence of stakes, at a constant distance from the central stake.

How long is the perimeter (a circumference) relative to the radius? The answer will always be the same ratio and one can compare the two lengths by putting a rope once around the fence, and comparing the radius and perimeter ropes side-by-side. Units of measure do not need to exist: the radius rope could be of any length and, alongside the perimeter rope, the radius rope could be laid end-to-end. There would be more of the perimeter rope left over, an excess of X (figure 1). So the value (of 2 x π) must be greater than six radius lengths.

This excess over six radii could be recorded as a short wooden rod (X in length). Once more, the number of rods can be divided into the perimeter rope 22 times to leave a new excess Y, which is noticeably half of X.

The new excess divides into the radius rope 7 times, with no excess, and into the perimeter rope 44 times, with no excess; leading to the most common ancient ratio for π in the megalithic world: the circumference accurately expresses 44 times the radius as 7, accurate to one part in 2500.

It was therefore possible for the megalithic astronomers to quantify π, and arrive at a “good” formulaic ratio for π of 22/7 (3.142857), which then means that any radius rope of the same seven units “could be counted on” as having 44 of the same units on its perimeter.

Taking an arbitrary size about one foot long, the radial rope can be made seven feet long and the perimeter must then be 44 feet long. And because the diameter of this circle is naturally 14 units, one can make a square of equal perimeter by taking a perimeter rope and marking its four equal sections, each then 11 feet long. One then has four corners that just exceed the circle (figure 2, left).