Mathf.PI

Description

The infamous 3.14159265358979... value (Read Only).

var radius : float = 5;

function Start() {
    var perimeter : float = 2 * Mathf.PI * radius;
    Debug.Log("The perimeter of the circle is: " + perimeter);
}

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour {
    public float radius = 5;
    void Start() {
        float perimeter = 2 * Mathf.PI * radius;
        Debug.Log("The perimeter of the circle is: " + perimeter);
    }
}