"fillamount" not appear!

Hello everyone, i have little problem.. i can't solve it. I'm totally newbie in c# and Unity!

in condition, i want to create radial loading bar, and see tutorial from youtube. but the problem is "fillamount" not appear! Whats is my problem?

"Assets/01_Scripts/02_Loading/LoadingARSkel.cs(29,55): error CS1061: Type Image' does not contain a definition for fillAmount' and no extension method fillAmount' of type Image' could be found (are you missing a using directive or an assembly reference?)"

there is myscript!

LoadingScript.cs

 using UnityEngine;
 using System.Collections;
 using UnityEngine.UI;
 
 public class LoadingScript : MonoBehaviour
 {
     public Transform RadialProgress;
     public Transform NilaiLoading;
     public Transform LoadingText;
 
     [SerializeField]private float currentAmount;
     [SerializeField]private float Kecepatan;
 
     void Update () 
     {
         if (currentAmount < 100) 
         {
             currentAmount += Kecepatan * Time.deltaTime;
             NilaiLoading.GetComponent<Text>().text = ((int)currentAmount).ToString()+"%";
             LoadingText.gameObject.SetActive(true);
         } 
         else
         {
             LoadingText.gameObject.SetActive(false);
             NilaiLoading.GetComponent<Text>().text="Selesai!";
             Application.LoadLevel("SceneLanjut");
         }
 
         RadialProgress.GetComponent<Image> ().fillAmount = currentAmount / 100;
     }
 }