Pi Approximation Day

Pi Approximation Day is celebrated every year on July 22 in honor of the mathematical constant π (pi), which approximates to 22/7 or roughly 3.14. While some mathematicians take the day seriously, many prefer a fun approach—like baking pies to mark the occasion. After all, the number pi is essential for countless mathematical calculations, especially those involving circles.

History

The history of pi spans more than 4,000 years. The ancient Babylonians approximated pi as 3.125 and used it to calculate circular dimensions. Around 250 BC, Greek mathematician Archimedes made a major breakthrough, calculating that pi lies between 3 1/7 and 3 10/71. Pi is also known as the Archimedes constant in his honor.

Centuries later, Chinese mathematician Zu Chongzhi confirmed Archimedes’ findings using independent methods, unaware of the original work, which had been lost. Indian scholars between 1400 and 1500 AD also calculated approximations of pi. In the 17th century, Austrian astronomer Christoph Grienberger calculated pi to 38 digits. In the mid-20th century, computers began to take over, and pi was calculated to 2,037 digits for the first time.

Interesting Facts

• The Greek letter π wasn’t used to represent pi until the 18th century, when it was introduced by Welsh mathematician William Jones.
• In 1973, pi was calculated to one million digits.
• Google employee Emma Haruka Iwao set the world record by calculating 31 trillion digits of pi. Her achievement is listed in the Guinness Book of Records.
• Rajveer Meena, a student at VIT University in India, memorized 70,000 digits of pi. It took him nearly 10 hours to recite them all.
• It is believed that the ancient Egyptians used pi in the construction of the pyramids.

How to Take Part

Celebrate by baking a pie, memorizing digits of pi, or competing with friends to see who can remember the most. It’s a fun way to improve memory and impress others with your math skills. Whether you’re a serious math lover or just in it for the dessert, July 22 is a great time to engage your brain and enjoy something sweet.

When is Pi Approximation Day in 2025?

Pi Approximation Day is observed annually on July 22.

Observations