
Pi Approximation Day 2025: What is it and why is it celebrated?
Pi Approximation Day, also known as Casual Pi Day, is celebrated annually on July 22nd. The day recognises and appreciates the mathematical consonant of pi (π), which is known in various aspects of maths and science.
What is Pi
Approximation Day?
Image credits: Getty Images
Pi is a special unit in mathematics. Presenting the relationship between a circle's circumference and diameter, the ratio of the two is stated as a constant pi.
The symbol of π was first introduced in 1706 by William Jones, a British mathematician. However, it became famous and came to be widely used due to Leonhard Euler, a Swiss mathematician who helped popularise it in his work.
Why is Pi Approximation Day celebrated?
Pi Approximation Day is celebrated on July 22nd every year, as this date is special.
When you divide 22 by 7, you get 3.142857, a number that is very close to the actual value of pi, which is about 3.14159. Since 22/7 is a convenient and easy way to remember the value of pi, the day serves as a reminder of its value. This is why it is also called Casual Pi Day, a more relaxed way of celebrating the symbol without delving into the complex digits.
Pi Day, is usually celebrated on March 14th, as 3/14 is a more popular meaning of the mathematical consonant.
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What is the
significance of Pi
(π)?
Image credits: Getty Images
The symbol of pi has existed for almost 4000 years. In ancient Babylon, people calculated the area of a circle by taking 3 times the square of its radius, making pi's value 3. A Babylonian tablet indicated the value of pi as 3.125, which is a close approximation. As per the Rhind Papyrus, ancient Egyptians calculated the area of a circle by a formula that gave the value of pi as 3.1605.
However, the first calculation of pi was completed by Archimedes of Syracuse, who is known as one of the greatest mathematicians of the ancient world.
He made use of Pythagoras' Theorem to find the areas of two regular polygons and reached a value approximation between 3 1/7 and 3 10/71.
After being introduced by Jones in 1706, mathematicians began using the symbol π for pi.
While for some, π has created a lot of difficulties in mathematical calculations, those who love the art of maths love the symbol. In both cases, it remains a vital and memorable symbol in the world of mathematics and the life of every student.
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