On March 14, 1988, American physicist Larry Shaw held the first-ever event to celebrate Pi (π) Day. Demonstrating ingenuity, he scheduled the celebration at 1:59 PM, aligning with the approximate value of π, 3.14159.
π is an irrational and transcendental number representing the ratio of a circle’s circumference to its diameter. This means that the digits after the decimal point continue infinitely without any repeating pattern. As a fundamental constant, π is widely used in mathematics, science, and engineering.
Since ancient times, π has intrigued mathematicians as a mysterious number. Around 1900 BCE, the Babylonians estimated π as 25/8 (3.125). Around 1650 BCE, the Egyptian scribe Ahmes calculated it as 256/81 (approximately 3.16). In the 3rd century BCE, Archimedes used inscribed and circumscribed regular polygons to prove that π lies between 3 10/71 and 3 1/7. π was also calculated in China during the 3rd century and India during the 5th century.
In the 17th century, mathematicians used infinite series to calculate π more precisely. In the 18th century, Johann Heinrich Lambert proved that π is an irrational number, and in the 19th century, Ferdinand von Lindemann demonstrated that π is transcendental.
Since 1988, Pi Day has evolved into a global celebration enjoyed by math enthusiasts and people worldwide. In 2009, the United States House of Representatives officially recognized Pi Day, further emphasizing its significance.
Today, many events commemorate Pi Day, including competitions to memorize the most digits of π, various math-related activities, and lectures. Most notably, just as Larry Shaw did at the first celebration, many people mark the occasion by sharing and enjoying circular pies in honor of Pi Day.