binahyeseira-
my brain has no clue what pi is
Pi is a number between 3 and 4. A convenient number, but just a number.
so first question that comes to my brain is what does pencils falling on a table have to do with pi.
You know that a circle’s circumference is 2*r*pi. You also know that a full circle has 360 degrees. Putting the two together, you get a convenient way to measure angles without using degrees called radians. Mathematicians use radians instead of degrees as a way of further alienating the non-mathematical population. Also because it can be more convenient.
A full circle has 360 degrees and 2*pi radians. If you want to say 90 degrees in radians, it would be pi /2 (because 90 is 1/4 of 360). Now you know how any problem that involves angles involves pi.