# International pi day brings sweet knowledge

Entire day dedicated to honoring the planet’s most enigmatic number. Elizabeth Kaiser graphic.

Every March 14, the number pi, represented by the Greek symbol π and derived from the first letter of the Greek word perimetros, meaning circumference. It is commemorated around the world. Pi is the symbol used in mathematics and physics which defines the ratio of the circumference of a circle to its diameter, which is just about 3.14159. In simpler terms, pi is used to calculate the distance around a circle by finding the distance across the circle and then multiplying that amount by pi.

One of the unique characteristics of the number pi is that it’s irrational, meaning it has an infinite number of digits. It has been calculated to over one trillion digits beyond its decimal point, but because of our limited calculation capabilities, the calculations based off pi will never be completely and truly accurate.

Although it took a long time for mathematicians to calculate the later digits of pi, it has been suggested that the Great Pyramids of Giza were built on the principles of pi. The ancient Babylonians also used a similar number – 3.125 – to aid in the construction of their buildings, which were built approximately 4,000 years ago. However, it was Chinese mathematicians who determined the first seven digits of the number in fifth century CE, an impressive feat before the age of computers. Famed mathematicians, such as Isaac Newton and Gottfried Leibniz have also made major contributions to the definition and calculation of pi.

Since pi does not have any clear pattern, some people try to memorize as many digits of it as they can. The world record holder for this is able to recite over 7,000 digits of the number. The number pi is also sometimes used to test the power of a computer’s computer processing unit. The more digits of pi the computer can calculate, the faster and more powerful the computer is.

People commemorate pi day with numerous different activities, including eating pie, throwing pies, and discussing the significance of the number pi. Since pie and pi are homophones in English, and because of the coincidentally circular nature of a pie, the delicious confection is typically used to celebrate the day. The day has been used to increase awareness of the importance of mathematics, as well as the potential fun to be found in it. March 14 is also notable for being Albert Einstein’s birthday, as well as the day on which physicist Steven Hawking died.