Using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks;
namespace ConsoleApplication8 { class Program { public static int S, a; static void Main(string[] args) { double S; Console.WriteLine("Введите a: "); var a = int.Parse(Console.ReadLine()); S = (Math.Pow(a, 2) * 3 * Math.Sqrt(3)) / 2; Console.WriteLine($"f({a})={S:0.00}"); Console.ReadKey(); } } }