double h;
            double c;
            double s;
            var a = c = h = s = 0;
            int num = rnd.Next(0, 4);
            int value = rnd.Next(4, 25);
            num = 0;
            switch (num)
            {
                case 0:
                    a = value;
                    s = 0.5 * a * a;
                    c = Math.Sqrt(2)*a;
                    h = 0.5 * c * a;
                    break;
                case 1:
                    c = value;
                    a = c / Math.Sqrt(2);
                    h = 0.5 * c * a;
                    s = 0.5 * a * a;
                    break;
                case 2:
                    h = value;
                    a =h/Math.Sqrt(2)/2;
                    s = 0.5 * a * a;
                    c = Math.Sqrt(2)*a;
                    break;
                case 3:
                    s = value;
                    a = Math.Sqrt(2*s);
                    c = Math.Sqrt(2)*a;
                    h = 0.5 * c * a;
                    break;
            }

            Console.WriteLine($"Катет a = {a:F4}\nГипотенуза c = {c:F4}\nВысота, опущенная на гипотенузу h ={h:F4}\nПлощадь S ={s:F4} ");