How to make this script find distance inside radius?

In this script I need to find the distance between the gameObject and the collider it's hitting if it's inside the radius.

 #pragma strict
 
 var wake : boolean;
 
 var power : float = 1500;
 var damage : int = 1;
 var radius : float = 5;
 
 var explodeSound : AudioClip;
 
 function Start () {
     yield WaitForSeconds (5);
     wake = true;
 }
 
 function Update () {
     if(wake == true) {
         Explode();
         wake = false;
         Destroy(gameObject);
     }
 }
 
 function Explode() {
  
     var colliders : Collider[] = Physics.OverlapSphere (transform.position, radius);
         for (var collider : Collider in colliders) {
             //if (collider.tag == "brick" || collider.tag == "player") {
                 var hit : RaycastHit;
                 if (Physics.Linecast(transform.position, collider.transform.position, hit)) {
                     if (hit.collider == collider) {
                         if (hit.rigidbody)
                             hit.rigidbody.AddExplosionForce(power, transform.position, radius, 3.0);
                 }
             }
         }
     //}
 }