Cant call method with array argument c#

Question

Im following a tutorial based on SOLID principles but i fail to understand how to actually implement this method, here is the tutorial Link

I faily understand the concept of the code but i cant figure out how to actually call the AreaCalculator.Area method from my Main

How do i call the method to either calculate the Rectangle Area or the Circle Area? based on the code in the tutorial

Area(Circle with 10 radius);
Area(Rectangle with 10 width and 5 height);

Shape.cs

public abstract class Shape
{
    public abstract double Area();
}

Circle.cs

    public class Circle : Shape
    {
        public double Radius { get; set; }
        public override double Area()
        {
            return Radius * Radius * Math.PI;
        }
    }

Rectangle.cs

    public class Rectangle : Shape
    {
        public double Width { get; set; }
        public double Height { get; set; }
        public override double Area()
        {
            return Width * Height;
        }
    }

AreaCalculator.cs

public static double Area(Shape[] shapes)
        {
            double area = 0;
            foreach (var shape in shapes)
            {
                area += shape.Area();
            }

            return area;
        }

Thank you

Answer 1

var circle = new Circle { Radius = 10 };                  // Create a circle
var rectangle = new Rectangle { Width = 10, Height = 5 }; // Create a rectangle

var shapes = new Shape[] { circle, rectangle };           // Create array of shapes

double area = AreaCalculator.Area(shapes);                // Call Area method with array

---

If you only need the area of a single shape, the AreaCalculator is unneccesary; simply call the Area method on an individual shape:

double circleArea = circle.Area();
double rectangleArea = rectangle.Area();