Area of Polygon-triangle and rectangle

public class Area
{
    public static double AreaPolygon(int[] x, int[] y, int noOfPoints)
    {
        double area = 0;
        for (int i = 0; i < noOfPoints; i++)
        {
            area = area + ((x[i] * y[i+1]) - (x[i + 1] * y[i]))
        }
        area = area * 0.5;
        return area;
    }

    public static double AreaTriangle(int b, int h)
    {
        return (b * h) * 0.5;
    }

    public static double AreaRectangle(int l, int h)
    {
        return (l * h);
    }
}