Here are some Facts you may not have known about Pi

• Pi is the circumference over diameter of a circle
• There is no zero in the first 31 digits of Pi.
• Pi is irrational.
• The Bible uses a value of Pi of 3. Here is a verse from I Kings 7,23: And he made a molten sea, ten cubits from one brim to the other: it was round all about, and his height was five cubits: and a line of thirty cubits did compass it about.
• The letter Pi was first used by Welshman William Jones in 1706 and was later adopted by Euler and soon became a standard notation
• Pi is the 16th letter of the Greek alphabet.
• A long time ago people thought there was an illness attached to trying to 'square a circle' called Morbus Cyclometricus
• Since the digits in Pi appear random and since the digits do not stop, it is possible in theory to hide messages and even software in Pi.
• Pi in base Pi is 10
• At position 763 there are six nines in a row. This is known as the Feynman Point
• In 240 B.C., Archimedes determined pi to be between 223/71 and 22/7
• In 150 A.D., Ptolemy determined pi to be approximately 377/120
• In 480 A.D. in China, pi was found to be approximately 355/113
• In 1150 A.D. Bhaskara determined pi to be approximately 3927/1250
• In 1579, Viete determined pi correctly to 9 decimal places by using polygons that had 393,216 sides.
• In 1610, Van Ceulen used a 2^62 sided polygon to compute pi to 35 decimal places
• In 1650, John Wallis said pi/2 = Gamma(2i)(2i) / Gamma(2i-1)(2i-1) with i=1,2,3…
• In 1674. Leibnitz said pi/4 = Sigma(-1)^i / (2i+1) with i=0,1,2,3…
• In 1949, the ENIAC computed pi to 2,037 decimal places after 70 hours
• In 1986, Cray-2 Supercomputer computed pi to 29,360,128 decimal places after 28 hours
• In 1988, Yasumasa Kanada computed pi to 201,326,000 decimal places
• In 1990, The Chudnovsky brothers computed pi to 1,011,196,691 decimal places
• In 1999, Pi is computed to 206,158,430,000 decimal places by Yasumasa Kanada and Daisuke Takahashi.
• In 2002, Pi is computed to 1,240,000,000,000 decimal places by Professor Yasumasa Kanada.
• “I prefer pi” is a palindrome
• Einstein's birthday is March 14, which is the 3rd month, 14th day or 3.14
• In Carl Sagan's science fiction novel Contact, Sagan contemplates the possibility of finding a signature embedded in the base-11 expansion of ? by the creators of the universe. • In the Star Trek episode "Wolf in the Fold", when the computer of the Enterprise is taken over by an evil consciousness, Spock tells the computer to figure Pi to the last digit, which incapacitates the entity as all computer resources are devoted to this impossible task.

Even with all the calculated decimal places of pi, if you had a circle the size of the observable universe, and you wanted to compute its circumference with accuracy equal to the size of a proton, the number of digits of pi that you'd need is only 50.

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