Pi Day is observed every year on **March 14**, and it is a day to commemorate the mathematical constant of Pi. It is only a fun observance, and as such, businesses and schools are open as usual.

**Why is Pi Day celebrated on March 14?**

In the American month/day way of writing a date, Pi Day happens on 3/14. 3.14 are the first three digits of Pi. If you love maths, you can have your Pi Day celebrations at exactly 1:59 a.m or p.m, so that they happen at exactly 3.14159.

Some math lovers also celebrate Pi Approximation Day on July 22, as 22/7 is the fraction that represents Pi.

**What is Pi?**

Pi is a mathematical constant that defines the ratio of the circumference of a circle in relation to its diameter.

The first calculation of Pi was done by Archimedes, a mathematician in Ancient Greece, who determined the area of a circle by using the Pythagorean theorem.

Since then, Pi has been used throughout history by many different cultures, and it has become an essential part for calculations in many fields such as engineering, construction and physics.

Pi is an irrational and transcendental number, which means it can go on to infinity. In fact, currently, Pi has been calculated by scientists to over 1 trillion decimal places and counting. However, it is usually abbreviated to be used in problem-solving

The word Pi comes from the Greek word perimetros, which means circumference, and the Greek letter has been used to represent it since the 18th century.

**History of Pi Day**

In 1988 physicist Larry Shaw held the first Pi Day celebration at the San Francisco Exploratorium, a science museum. On that day, people commemorated Pi by having circular parades and eating fruit pies.

March 14 became officially recognized as National Pi Day in the United States by the House of Representatives on March 12, 2009.

**Celebrating Pi Day**

Many people celebrate Pi Day by eating pies and organizing pie-eating contests. There are also competitions to see who can recall Pi to the highest number of decimal places.

The San Francisco Exploratorium still hosts yearly celebrations on March 14, and they now include webcasts.

**Some Pi facts**