**Pi**: The value of PI is infinite, means pi is an irrational number, meaning that its decimal form neither ends (like 1/4 = 0.25) nor becomes repetitive. That’s why we consider the value of Pi as 3.14.

It’s been an official national holiday since 2009. March 14 marks Pi Day, an annual celebration of the mathematical sign pi. Founded in 1988 by physicist Larry Shaw, March 14 was selected because the numerical date (3.14) represents the first three digits of pi, and it also happens to be Albert Einstein’s birthday.

**Facts about Pi value:**

- Pi is all encompassing.
- Pi is ancient.
- We’ve used computers to calculate pi to more than 22 trillion digits.
- Humans have memorized vast stretches of pi.
- Pi has a bit part in many books and movies.
- Even rocket scientists only need a bit more than a dozen decimal places.

The symbol of the Pi is **“π”**, which is written as the Greek letter, is the ratio of the circumference of any circle to the diameter of that circle. Regardless of the circle’s size, this ratio will always equal pi. In decimal form, the value of pi is approximately 3.14.

**Experiment**: Try a brief experiment: Using a compass, draw a circle. Take one piece of string and place it on top of the circle, exactly once around. Now straighten out the string; its length is called the circumference of the circle. Measure the circumference with a ruler. Next, measure the diameter of the circle, which is the length from any point on the circle straight through its center to another point on the opposite side. (The diameter is twice the radius, the length from any point on the circle to its center.) If you divide the circumference of the circle by the diameter, you will get approximately 3.14—no matter what size circle you drew.