(CNN) — If you're using Pie Day as an excuse to eat pie, there's a lot more to know about pie.

On March 14, here's why we care about pie and its day of celebration.

What is pie?

Pi is the ratio of a circle's circumference to its diameter, or approximately 3.14.

What is Pi Day?

Pi Day occurs on March 14th because in the US the date is written as 3/14. If you're a math whiz, celebrate the day by hitting the first six digits of pi at exactly 1:59 am or 3.14159 pm.

March 14th is Albert Einstein's birthday.

History of Pi Day?

Physicist Larry Shaw started Pi Day in 1988 at the Exploratorium in San Francisco to celebrate popular numbers and mathematics.

In 2009, the US House of Representatives passed a resolution to recognize Pi Day.

Who invented the bag?

The mathematical concept of pi has been around for thousands of years, but it was only known from Greek writing in the 18th century. Philologist William Jones began using the symbol in 1706, but it was popularized by mathematician Leonhard Euler.

Why is pie important?

Unless you're a mathematician or scientist, you probably don't see pi very often. But pi is essential for calculations in mathematics, engineering, construction, physics, and space exploration.

Does the pie ever end?

Like our love for pie, pie is infinite. Its exact value can never be calculated and it does not seem to have a form.

Here's the bag for the digit 10,000 If you want to recite it.

Who has the record for reading pie?

Rajveer holds the record of reading most decimal places of Meena Pi. In 2015, Meena recited 70,000 decimals blindfolded. It took almost 10 hours.

To know more about Pi, visit www.piday.org.