## When is Pi Day?

March 14th marks Pi Day, the holiday commemorating the mathematical constant π (pi), written numerically as 3.141592+. Since mathematic notation is a language that uses symbols from a multitude of alphabets and typefaces, it seems only fitting that this sixteenth letter of the Greek alphabet gets a little attention.

## Where is the word *pi* from?

The Latin name of the Greek letter π is *pi*, pronounced “pie.” The first recorded use of the letter as a mathematical symbol comes from the Welsh mathematician William Jones in a 1706 work called *Synopsis Palmariorum* in which he abbreviated *periphery* or its Greek ancestor *περι**ϕ**έρεια**,* meaning “circumference,” to π.

## What does *pi *mean in mathematics?

The mathematical *pi *is defined as the ratio of the circumference of a circle to its diameter. As an irrational number, pi can never repeat when written in decimals; computers have calculated pi to decimal places in the trillions. It is also a *transcendental* number, a concept that exceeds the capacity of this post.

Memorizing as many digits of pi as possible is an obsession for some. The Guinness World Record for memorizing digits of π is held by a man named Lu Chao. He set the record in November, 2005 at Northwest A&F University in the Shaanxi province of China. It took him 24 hours and 4 minutes to recite the 67,890th decimal place of π without a mistake.

Wow, that’s commitment.