nilai karat pi
use std::f64::consts::PI;
// or
let pi = std::f64::consts::PI;
// or as a literal
const pi: f64 = 3.141592653589793;
Mackerel
use std::f64::consts::PI;
// or
let pi = std::f64::consts::PI;
// or as a literal
const pi: f64 = 3.141592653589793;