How to pause a game with a GUI button

I know how to create a pause menu and how to access it and pause the game via pressing the escape button.

I am developing a mobile game so how would I do it with a gui button instead of a key press.

How would I do this?

using UnityEngine;
using System.Collections;

public class Pause : MonoBehavior
{
	// Has the game been paused?
	private bool isPaused;
	// Has the game gone through it's pause transition?
	private bool hasPaused = false;
	
	public void Start()
	{
		// Default to not paused.
		this.isPaused = false;
	}
	
	public void OnGUI()
	{	
		// If you're paused
		if(this.isPaused) {
			// And nothing has initialized
			if(!this.hasPaused) {
				// Pause the game
				this.pauseGame();
				this.hasPaused = true;
			}
			// GUI changes.
		} else {
			if(this.hasPaused) {
				this.resumeGame();
				this.hasPaused = false;
			}
		}
		
		// If you click the button,
		if(GUI.Button(new Rect(100,100,100,100), "PAUSE")) {
			// Toggle the games pause state.
			this.changePauseState();
		}
		
	}
	
	public void pauseGame()
	{
		// Pause the game
		Time.timeScale = 0;
		// Any other logic
	}
	
	public void resumeGame()
	{
		// Resume the game
		Time.timeScale = 1;
		// Any other logic
	}
	
	public void changePauseState()
	{
		// Alternate bool value per button click
		this.isPaused = !this.isPaused;
	}
}