Creating Classes (RESOLVED)

[JAtkinson]

Why does VS.net let you use System.Math.Abs(double) without creating a new instance of it (System.Math math = new System.Math)? Ive been trying to make my own class that will find the area of circle, but it makes me create a new object first (ADGMathPro.Circle circle = new ADGMathPro.Circle();

What I was it to be able to do this....

ADGMathPro.Circle.Area(34);
instead of
circle.Area(34);

namespace ADGMathPro
{
   /// <summary>
   /// Summary description for Circle.
   /// </summary>
 
public class Circle
     {
        
const double pi = System.Math.PI;
 
public double Area(double radius)
    {
        double area;
        area  = pi * (radius * radius);
        return area;
    }
 
public double Circumference(double radius)
    {
        double circumference;
        circumference = 2 * pi * radius;
        return circumference;
    }
 
}
}

What am I doing wrong??

Thanks