What Is the Secret Behind the Number π?

Imagine you have a round pizza. If you measure the distance around it, that’s circumference, and then divide it by how wide it is, that’s the diameter, like from one side to the other, you always get the same number, no matter how big or small your pizza is. That number is called π (pi), which is about 3.14. It shows up in everything from wheels to waves because circles are everywhere.