the beauty of 3.1415... Physicist Larry Shaw is known as t "Prince of Pi" as he officially declared March 14 as pi day. Pi wasn't always know as pi. People referred to it as "the quantity which when the diameter is multiplied by it, yields the circumference. The greek letter π is the first letter of the word periphery and perimeter. The symbol pi was introduced by William Jones and was adopted by Leonard Euler in the 1700s. And as we all know, pi is the ratio of a circle’s “periphery” to its diameter. All the digits of pi can never fully be known as it is an "infinite decimal". In a circle, if you divide the circumference (is the total distance around the circle) by the diameter, you will get exactly the same number. Whether the circle is big or small, the value of pi remains the same.