It's Pi Day! No, that's not a typo and we're not talking about the delectable dessert dish, though many do use the holiday to treat their sweet tooth.

We're talking about the day we celebrate the incredibly unique, long and limitless number of pi.

### So, what is pi?

For starters, the value of pi is approximately 3.1415926535.

It's a mathematical constant that represents the ratio of the circumference of a circle to its diameter.

It's also an irrational number, meaning it cannot be expressed as a finite fraction or decimal and it goes on infinitely, never repeating.

Pi is used in a variety of scientific and mathematical calculations, particularly in geometry, trigonometry, astronomy and physics.

It is celebrated around the world on March 14, or 3/14, because 3.14 are the first three digits of pi.

### How pi helps astronomers locate habitable planets

On Pi Day, astronomers use pi to make big discoveries.

### 10 facts about pi

**1.** The symbol for Pi has been around for over 250 years and it was first introduced by Welsh mathematician William Jones in 1706. It was later popularized by mathematician Leonhard Euler.

**2.** In 2015, Rajveer Meena set the world record by reciting 70,000 decimals of pi. It took 10 hours!

**3.** In 2021, Emma Haruka Iwao used Google cloud technology to set another world record by calculating pi to more 31.4 trillion decimal places.

**4.** Egyptian mythologists believe the Pyramids of Giza were built using pi because the height of the pyramids have the same relationship with the perimeter of the base as the relationship between a circle's radius and circumference.

**5.** While pi is incredibly long, the sequence 12345 doesn't appear anywhere in the first million digits.

**6.** Albert Einstein was born on Pi Day.

**7.** On March 12, 2009, the U.S. House of Representatives passed a resolution designating March 14 as Pi Day.

**8.** The calculation of pi is used as a stress test for computers.

**9.** Since the exact value of pi can't be calculated, we can never find the exact area or circumference of a circle — but we can get really close.

**10. **You can also score some nice discounts at many pizzerias on Pi Day.

*For even more fun facts about pi, visit **piday.org.*

### How we celebrate Pi Day

Pi Day is celebrated in many different ways, with many people — you guessed it — eating pie.

Others who are more competitive may join pi reciting contests. You already know the current world record, so good luck.

Many schools, museums and science centers also hold events that include pi-themed art, workshops and experiments.

Overall, Pi Day is a great time to indulge yourself but also celebrate the beauty and importance of mathematics in our lives.

### 3 incredibly specific ways to celebrate Pi Day

Here are three ways to celebrate Pi Day that are as unique, long and specific as the number itself.