# The most irrational day of the year!

14th March has been officially designated Pi Day, a day for which we can celebrate the glorious number that starts with 3.14. Coincidentally, the 14th of March is also Albert Einstein’s birthday.

$$\pi$$ -the ratio of the circumference of a circle to its diameter- has been calculated to over one trillion decimal places. The record as far as I know belongs to Alexander J. Yee & Shigeru Kondo, who have calculated $$\pi$$ to 10 trillion digits [1]. As an irrational and transcendental number, $$\pi$$ will continue infinitely without any repetition or patterns emerging.

 The “pi man” Larry Shaw The first Pi Day was organized by Larry Shaw and held in San Francisco in 1988. In 2009, the US House of Representatives backed its official designation.

What to do for Pi Day?
Suggestions include bake a pie for Pi Day, or be artistic and write a piece of music, a poem or make a painting. You can find lots more suggestions by following this link.

The Welsh connection
The earliest known use of the symbol $$\pi$$ to represent the ratio of the circumference of a circle to its diameter is by Welsh mathematician William Jones FRS (1675 – 3 July 1749) in 1706 [2].

Portrait of William Jones by William Hogarth, 1740 (National Portrait Gallery)

Jones was a close friend of Sir Isaac Newton and Sir Edmund Halley. In November 1711 he became a Fellow of the Royal Society, and was later its Vice-President.

References
[1] Alexander J. Yee & Shigeru Kondo, Round 2… 10 Trillion Digits of Pi 2013.

[2] William Jones, Synopsis Palmariorum Matheseos, 1706.