The story of π (pi)

Starting from sixth grade, school children starts to come across the interesting symbol π. So what is so special about this Greek alphabet?

Pi, represented by the symbol π, is the ratio between circumference of a circle and its diameter. As early as 2500 years ago, people realize that there is a fixed relationship between these two values regardless of the size of the circle. However, people also realize that no matter how hard you try, you can only arrive at an approximation rather than the actual value of this quantity.

One of the most interesting properties of π is that it is an irrational (or incommensurable) number, meaning it can’t be constructed from the division of two integers. In other words, there is an infinite number of digits after decimal which don’t repeat in pattern if you want to write the value of it on paper. Around 5^th century, Chinese mathematician made the estimation for π to the precision of 7 digits after decimal. With the advent of supercomputers in recent years, scientists come up with more accurate estimation of π to the precision of 10 to the power 13 (10¹³) number of digits after decimal. In reality, we rarely need to know this intractable quantity by more than 100 digits after decimal for most scientific applications. Today, the search for better estimate of π is still going on. It is simply a way our scientists use to ascertain the power of the latest supercomputers.

In primary school, most teachers ask students to use 22/7 or 3.14 as the approximate value for the study of circle. For these school children, perhaps the most memorable aspect of π (pi) is the Hollywood blockbuster, “Life of Pi” (directed by Ang Lee) which won four Oscar Academy Awards in 2012.