Pi Day! What is Pi?

Pi is the ratio between a circle’s circumference and diameter. It’s a number used in many formulas associated with circles.

The circumference is the distance around the edge of a circle

Pi to two decimal places is 3.14.

The symbol for Pi was first introduced by a Welsh mathematician called William Jones in 1706.

Pi Day is March 14th, as 3.14 are the first three digits of pi.

Pi Day was first celebrated at San Francisco’s Exploratorium Museum.

Archimedes is thought to be the first person to have calculated the value of pi accurately.

Pi is an irrational number, meaning it goes on forever without repeating.

Astronomers have found a pi planet. It orbits its star every 3.14 days!

Pi is one of the most important constants in mathematics.

March 14th is also Albert Einstein’s birthday.

Last Updated on March 14, 2025 by Emma Vanstone