In a recent article, published on Pi Day, Gareth Ffowc Roberts, emeritus professor of Education at Bangor University, discusses how Welsh mathematician William Jones gave the world "an agreed symbol for the number." According to the author, "We typically think of this number as being about 3.14, but Jones rightly suspected that the digits after its decimal point were infinite and non-repeating. This meant it could never be 'expressed in numbers', as he put it. That was why he recognised the number needed its own symbol. It is commonly thought that he chose pi either because it is the first letter of the word for periphery (περιφέρεια) or because it is the first letter of the word for perimeter (περίμετρος), or both."
Happy Pi Day!