Mathf.Sqrt  

print(Mathf.Sqrt(10));

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
void Awake() {
print(Mathf.Sqrt(10));
}
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

def Awake():
print(Mathf.Sqrt(10))