Why does Pi show up in so many diverse equations if it’s only related to a circle?

Question

Is Pi more than just a ratio for circles? Is there a easy way to understand the universality of Pi?

In: 1018

Answer 1

The reason it shows up in weird and unexpected places like Euler’s identity (e^iπ + 1=0) is because of the complex number plane. Instead of numbers just going forward and backward on a number line, they can also go up and down and diagonal from the center point which makes it easy to create circles.