Barometer | 2 July 2011

Life of Pi


A group of mathematicians is campaigning for the mathematical constant pi to be replaced by tau, the latter being the ratio of the circumference to the radius as opposed to that of the circumference to the diameter. As tau is simply twice the value of pi (approximately 6.28) it won’t consume so many centuries to establish its value as pi.

— A value for pi is mentioned in the Old Testament relating to the construction of the Temple of Solomon around 450 bc. It sets a value of three, suggesting that the temple may have been very shoddily built. — In the 3rd century bc, Archimedes

calculated the value of pi to lie somewhere between 223/71 and 22/7, which is correct to three decimal places.

— The 5th-century Chinese mathematician Zu Chongzhi estimated pi at 355/113, correct to six decimal places.

— The real breakthrough came with a formula devised by a 17th-century British mathematician, which has enabled pi to be calculated by many thousands of places.