Centering Radial Menu

I'm attempting to make a radial menu whose center is that of a specified game object. Here is my code so far

 using UnityEngine;
 using System.Collections;
 
 public class RadialMenu : MonoBehaviour {
 
     public int buttonCount; //The number of buttons to be displayed
     public float radius;    //The radius of the circle
     public GameObject objectOfCenter;
 
     //C#
     void OnGUI()
     {
         float angleStep = Mathf.PI*2.0f / buttonCount;
         Vector2 circleCenter = new Vector2(objectOfCenter.transform.position.x,objectOfCenter.transform.position.y);
 
         // Set the circle radius
         for (int i = 0; i < buttonCount; i++)
         {
             Rect R = new Rect(0,0,40,20); 
             R.x = circleCenter.x + Mathf.Cos(angleStep*i)*radius - R.width/2;
             R.y = circleCenter.y + Mathf.Sin(angleStep*i)*radius - R.height/2;
         }
     }
 }
 

I feel like it should work, but when I run the game I get this.

That ring of buttons should be centered around the center point of that big ring on the right.

objectOfCenter = big circle on the right.

Any ideas?