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

I think pi is kind of fundamentally related to the “upscaling” of something from a lower dimensionality to a higher dimensionality (1D to 2D, 2D to 3D etc)