#### Transcript of The History of Pi Timeline

**The History of Pi Timeline**

2589 BC

The Great Pyramid at Giza was built with a perimeter of 1760 cubits and a height of 280 cubits, a ratio of 1760: 280 or approximately 2 Pi, which implies that Egyptian engineers had some idea of the concept of Pi.

Approx 1900 BC

Babylonian Astronomers wrote the first approximation of the value of Pi. This value is 25/8 or 3.125.

250 BC

Archimedes estimates the upper and lower bounds of Pi by calculating the perimeters of hexagons composing a 96 sided Polygon. He proved that 3,1408 < Pi < 3.1429.

265 AD

Chinese mathamatician Liu Hui creates polygon-based iterative algorithm and estimates that Pi is equal to 3.1416.

1424

Persian astronomer Jamshīd al-Kāshī produces 16 digits using a polygon with 3×2^28 sides which stands as a record for 180 years

1500 AD

First written description of an infinite series used to compute Pi written in Sanskrit by Indian astronomer Nilakantha Somayaji.

1593

French mathematician François Viète discover the first infinite sequence in Europe. Unlike most infinite series this was a infinite product rather than infinite sum.

1699 AD

Abraham Sharp used the Gregory–Leibniz series to compute Pi to 71 digits, breaking the previous record of 39 digits

1735 AD

Leonhard Euler solves the Basel problem, establishing connection between Pi and prime numbers.

1761 AD

Johann Heinrich Lambert proves that Pi is irrational.

1706 AD

William Jones, in his work Synopsis Palmariorum Matheseos; uses the Greek symbol currently used for Pi

for the first time.

1882 AD

German mathematician Ferdinand von Lindemann proves that Pi is transcendental.

Using a inverse tangent infinite series, a team of mathematicians lead by George Reitwiesner calculate 2,037 digits of Pi with a calculation that took 70 hours of computer time on the ENIAC computer

1949 AD

1975-76 AD

American physicist Eugene Salamin and Australian scientist Richard Brent publish the iterative algorithms, which uses prior calculations to calculate the following step.

1995 AD

Spigot algorithms are discovered. They work like water dripping from a faucet, calculating single digits of Pi instead of several strings at a time.

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