According to the website Angio, Pi (π) is the ratio of the circumference of a circle to its diameter.
It doesn't matter how big or small the circle is - the ratio stays the same.
Properties like this that stay the same when you change other attributes are called constants. Because it's so easily observed (you can measure it with a piece of string!), Pi has been popular for centuries.
Let us set aside some time today to celebrate everything that is
constant - death, taxes, sunrises and sunsets, etc.