class Figure
{
    private double _square;
    public double Square {
        get
        {
           return _square;
        }
    }
    //square
    public Figure(double a, double b)
    {
        _square = (a * b);
    }
    //trapezoid
    public Figure(double a, double b, double h)
    {
        _square = ((a + b) / 2) * h;

    }
    
}