What is Pi Day?

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Prelims: Current Affairs & Events
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Pi Day was recently celebrated worldwide to recognize the mathematical constant, Pi.

About Pi Day:

  • International Day of Mathematics, or Pi Day, is celebrated on March 14 every year to recognize the mathematical constant, Pi.
  • The day is celebrated by mathematics enthusiasts and educators worldwide to recognize and appreciate the significance of mathematics in our lives.
  • Why March 14?
    • The approximate value of Pi is 3.14. 
    • The date, when written in the format of month/day (3/14), matches the first three digits of the mathematical constant. 
  • History:
    • The first Pi Day was celebrated in 1988 by physicist Larry Shaw at the San Francisco Exploratorium.
    • In 2009, the United States House of Representatives designated March 14 as Pi Day.
    • UNESCO marked Pi Day as the ‘International Day of Mathematics' during its general conference in 2019.
    • Mathematician and physicist Albert Einstein, known for the "General Theory Of Relativity," was born on Pi Day in 1879.

What is Pi (π)?

  • Pi is a mathematical constant that represents the ratio of the circumference of a circle to its diameter. 
  • It is an infinitely long, irrational number, and its exact value cannot be known.
  • Pi is roughly equal to 3.14 or 22/7.
  • History:
    • Pi has been known for nearly 4,000 years and was discovered by the ancient Babylonians.
    • One of the first calculations of pi was carried out by Greek mathematician Archimedes of Syracuse (287 B.C. to 212 B.C.)
    • It also has a symbol, ‘π.’ The symbol π was devised by British mathematician William Jones in 1706.
  • Applications: It is used in a wide variety of mathematical and scientific calculations, including geometry, trigonometry, calculus, and more.


Q1) What is an irrational number?

An irrational number is any real number that cannot be expressed as the quotient of two integers—that is, p/q, where p and q are both integers. Irrational numbers such as π can be expressed as an infinite decimal expansion with no regularly repeating digit or group of digits. Together the irrational and rational numbers form the real numbers.

Source: Pi Day 2023: History And Significance Of This Mathematical Constant