How to correctly describe a method that finds the area of ​​a circle given a given radius?

Question

Unity

Describe a method that calculates the area of ​​a circle given a given radius. Returns a fractional number.
I can't figure out how to properly describe this method, my code is below:

void Start()
 {
   float  circle =Mathf.PI;
   float R= 3;
   float result=GetSquareofcircle(R);
 Debug.Log(result);
 }
 float GetSquareofcircle(float R)
{
float circlesquare = Mathf.PI *Mathf.Pow(R,R);
 return(circlesquare);
}

I would be grateful if you help)

Answer 1

float circlesquare = Mathf.PI *Mathf.Pow(R, 2 );
But, for squaring it is better not to use Pow.
float circlesquare = Mathf.PI * R * R;