Most people have heard of the mathematical constant Pi (?), and will know that it\u2019s roughly 3.14. Taking inspiration from these three digits, March 14 (3\/14 in the US date format) is heralded as international Pi Day<\/a>, first marked by US physicist Larry Shaw in 1988<\/a>.<\/p>\n This year brings a unique opportunity to demonstrate an entirely unnecessary degree of zeal by marking Pi Day correct to nine decimal places on March 14, 2015, at 9.26am 53sec \u2013 corresponding to 3.141592653, the first 10 digits of Pi. If you\u2019re too busy this weekend, you could book in July 22 \u2013 another way of expressing Pi approximately is the fraction 22\/7.<\/p>\n <\/p>\n Pi is calculated as the ratio between a circle\u2019s circumference to its diameter.<\/p>\n Pi is always the same value, no matter the size of the circle, which makes it an important mathematical constant.<\/p>\n The ancient Babylonians<\/a> calculated Pi as three by taking three times the square of the circle\u2019s radius, later refining the value to 3.125. Archimedes of Syracuse (287-212 BCE) approximated Pi by inscribing polygons on the inside and outside of a circle<\/a>. By increasing the number of sides of the polygons, Pi could be calculated to higher levels of accuracy.<\/p>\n Even today, calculating Pi to ever increasing levels of accuracy continues \u2013 it has now been found to an accuracy of over 13 trillion digits<\/a>. There\u2019s no reason to suspect this record will remain forever, even though only about 39 decimal places are sufficient for astronomical precision. There is no reason to be more precise for practical purposes but it is good scientific sport of sorts to strive to be ever more accurate.<\/p>\n Pi is an irrational number<\/a>, which means it cannot be accurately represented as a fraction, a<\/em>\/b<\/em>, where a<\/em> and b<\/em> are integers. An approximation is to express it as 22\/7 (3.1428\u2026) which is inaccurate by 0.04025%. A closer approximation is 104348\/33215<\/a>, which has a far smaller error of 0.00000001056% but is still, technically, wrong.<\/p>\n Pi is also a transcendental number<\/a> which, simplified, are numbers that cannot be reduced algebraically (more accurately a number that is not the root of any non-zero polynomial equation with rational coefficients).<\/p>\n The proof that Pi is transcendental was found in 1882, but it had been known for much longer that if Pi was transcendental then it would be impossible to square the circle<\/a> \u2013 to construct a square with the same area as a circle.<\/p>\n![\"\"](\"https:\/\/62e528761d0685343e1c-f3d1b99a743ffa4142d9d7f1978d9686.ssl.cf2.rackcdn.com\/files\/74079\/width237\/image-20150306-13585-zmqrq1.jpg\")
![\"\"](\"https:\/\/62e528761d0685343e1c-f3d1b99a743ffa4142d9d7f1978d9686.ssl.cf2.rackcdn.com\/files\/74694\/width668\/image-20150312-13499-1qlvsco.png\")
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\nGerman<\/a><\/span>
\n<\/figcaption><\/figure>\nSome Properties of Pi<\/h2>\n
![German<\/a><\/span>\n<\/figcaption><\/figure>\nSome Properties of Pi<\/h2>\nPi is an irrational number<\/a>, which means it cannot be accurately represented as a fraction, a<\/em>\/b<\/em>, where a<\/em> and b<\/em> are integers. An approximation is to express it as 22\/7 (3.1428\u2026) which is inaccurate by 0.04025%. A closer approximation is 104348\/33215<\/a>, which has a far smaller error of 0.00000001056% but is still, technically, wrong.<\/p>\nPi is also a transcendental number<\/a> which, simplified, are numbers that cannot be reduced algebraically (more accurately a number that is not the root of any non-zero polynomial equation with rational coefficients).<\/p>\nThe proof that Pi is transcendental was found in 1882, but it had been known for much longer that if Pi was transcendental then it would be impossible to square the circle<\/a> \u2013 to construct a square with the same area as a circle.<\/p>\n](\"http:\/\/commons.wikimedia.org\/wiki\/File:PI.svg\"){kind=link}