TriangleCalc

 class Triangle_Calc
    {
        public double SideA { get; set; }

        public double SadeB { get; set; }

        public double SadeC { get; set; }



        public double AreaCalc
        {
            get
            {
                return Math.Sqrt(((SideA + SadeB + SadeC) / 2) * (((SideA + SadeB + SadeC) / 2) - SideA)*(((SideA + SadeB + SadeC) / 2) - SadeB)*(((SideA + SadeB + SadeC) / 2) - SadeC));

            }
        }
        public double PerimeterCalc
        {
            get
            {
                return SideA + SadeB + SadeC;
            }
        }


        public override string ToString()
        {
            return string.Format("{0}", AreaCalc);
        }

    }








 static void Main(string[] args)
        {
            double SideATri = double.Parse(Console.ReadLine());
            double SideBTri = double.Parse(Console.ReadLine());
            double SideCTri = double.Parse(Console.ReadLine());

            Triangle_Calc tri = new Triangle_Calc { SideA=SideATri, SadeB=SideBTri, SadeC=SideCTri };

            Console.WriteLine($"Perimater: {tri.PerimeterCalc}");
            Console.WriteLine($"Area: {tri.AreaCalc}");
}