Pi, the mathematical constant, is widely considered one of the most intriguing numbers in mathematics. So captivating is this constant that its own day – National Pi Day was established by a San Francisco physicist in 2016 and celebrated on March 14 (3/14). But what exactly is Pi? And why does it hold such significance for mathematics?
Mathematicians have studied pi for over 4,000 years. Some of the greatest mathematicians such as Fibonacci, Newton and Leibniz devoted significant portions of their lives to exploring its properties and deciphering its digits.
Simply defined, pi is the ratio between a circle’s circumference and diameter. It is perhaps best known among mathematical constants and written out fully has an exact value of 3.141592654; when using calculators however, you are likely to get 3.14 as this can only display 10 digits at once.
Babylonians and Egyptians used rough numerical approximations of pi, which were refined by mathematicians in Ancient Greece – such as Archimedes – before truly accurate methods were developed by mathematicians in the 1600s using geometric approaches that inscribed polygons inside circles and gradually added sides until eventually approaching the actual radius of a circle.
Today, due to computer power, mathematicians can quickly calculate large numbers of digits of pi. Indeed, its significance has led it to be celebrated annually on March 14 – not to mention its use in many scientific and technological applications.
Scientists use pi to make calculations about planet sizes, the composition of asteroids and how much fuel a spacecraft needs for transport to the moon. Furthermore, Pi is even used when designing motors, cars and airplanes!
Pi is also useful when studying patterns, like those seen on zebra stripes or leopard spots. Scientists can use it to investigate these patterned structures by finding their size and spacing to gain greater insight into how they came to exist.
If you want to learn more about Pi, this blog article from Raspberry Pi provides the answers. Baylor math chair Dorina Mitrea discusses what makes this infinite number special while offering ways of celebrating National Pi Day.