public double AreaSquare()
        {
            var check = new InputCheck();

            double input = check.Checker();

            double area = Math.Pow(input, 2);

            return(area);
        }
        public double SidesTriangle()
        {
            var input = new InputCheck();

            double[] sides = { 1, 2 };

            Cathet1 = input.Checker();

            sides[0] = Cathet1;

            Cathet2 = input.Checker();

            sides[1] = Cathet2;

            return(sides[]);
        }