Circumference.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Circumference : MonoBehaviour
{
    [SerializeField] private Transform _target;
    [SerializeField] private List<Transform> _surrounders;
    [SerializeField] private float _radius;

    private void Update()
    {
        float angleStep = 360 / _surrounders.Count * Mathf.Deg2Rad;

        for (int i = 0; i < _surrounders.Count; i++)
        {
            float angle = angleStep * i;
            Vector2 localPosition = new Vector2(Mathf.Cos(angle), Mathf.Sin(angle)) * _radius;

            _surrounders[i].position = new Vector3(_target.position.x + localPosition.x,
                _surrounders[i].position.y,
                _target.position.z + localPosition.y);
        }
    }
}