Five Fascinating Facts about Pi
Some of the many ways that this fundamental constant of nature surprises us
The knowledge that a constant of nature exists in the geometry of circles has been around for more than 4000 years. The ancient Babylonians used to estimate the area of a circle by squaring its radius and multiplying their answer by three. Thus, the very first estimate of Pi was 3. There is evidence, though, that the Babylonians refined this value over time, with one tablet dating from around 1700 BC stating the value of Pi as 3.125. Not long after that the Egyptians had suggested a value of 3.1605. Not bad for ancient peoples.
As far as we know, it was Archimedes who proposed the first formal method for estimating Pi. He proposed a method where a regular polygon is inscribed inside a circle and then a larger regular polygon is constructed in which the circle is circumscribed. The areas of these two polygons could be calculated using the Pythagorean Theorem (which was relatively newly discovered at the time), and Archimedes proposed that the area of the circle lay somewhere in between these two areas. He used this method to show that Pi’s value was between 22/7 and 223/71.
