# Happy Pi Day Pi Day is celebrated every March 14 (3/14) around the world, so bakers and mathematicians alike can celebrate it today.

Pi in the original Greek is represented by “π,” the symbol used in mathematics to represent a constant — the ratio of the circumference of a circle to its diameter — which is approximately 3.14159, or 3.14 for short, no matter the size of the circle.

However, there is not much that is short about pi. It appears to be an infinite number that has been calculated to more than one trillion digits beyond its decimal point. That makes it what is referred to as an “irrational” and “transcendental” number that will continue infinitely without repetition or pattern. While only a handful of digits are needed for typical calculations, Pi’s infinite nature makes it a fun challenge to memorize, and to computationally calculate more and more digits.

By measuring circular objects, it has always turned out that a circle is a little more than three times its width around.

The theory behind the measurement of a circle is ancient. In the Old Testament of the Bible (1 Kings 7:23), a circular pool is referred to as being 30 cubits around, and 10 cubits across. The ancient mathematician Archimedes (born circa 287 B.C.) used polygons with many sides to approximate circles and determined that Pi was approximately 22/7. The symbol (Greek letter “π”) was first used in 1706 by William Jones.  A “p” was chosen for “perimeter” of circles, but the use of “π” became popular after it was adopted in 1737 by the Swiss mathematician Leonhard Euler.

Now you know more about pi. If that’s not enough, go bake a pie and enjoy!