Check out example codes for "unity 2d rotate towards direction". It will help you in understanding the concepts better.

Code Example 1

``````/// <summary>
/// Rotate a gameobject to face a direction in 2D space with offet
/// </summary>
/// <param name="target"></param>
/// <param name="RotationSpeed"></param>
/// <param name="offset"></param>
private void RotateGameObject(Vector3 target, float RotationSpeed, float offset)
{
//get the direction of the other object from current object
Vector3 dir = target - transform.position;
//get the angle from current direction facing to desired target
float angle = Mathf.Atan2(dir.y, dir.x) * Mathf.Rad2Deg;
//set the angle into a quaternion + sprite offset depending on initial sprite facing direction
Quaternion rotation = Quaternion.Euler(new Vector3(0, 0, angle + offset));
//Roatate current game object to face the target using a slerp function which adds some smoothing to the move
transform.rotation = Quaternion.Slerp(transform.rotation, rotation, RotationSpeed * Time.deltaTime);
}``````

Code Example 2

``````private void RotateGameObject(Vector3 target, float RotationSpeed, float offset)
{