Not sure why my code isn't compiling - what am I missing on this one?

namespace Treehouse.CodeChallenges
{
    class FrogStats
    {
        public static double GetAverageTongueLength(Frog[] frogs)
        {
            double sumTotal = 0;
            for(int i = 0; i < frogs.Length; i++)
            {
                sumTotal = sumTotal + frogs[i];
            }
            var averageTongueLength = sumTotal / frogs.Length;
            return averageTongueLength

        }

    }
}

namespace Treehouse.CodeChallenges
{
    public class Frog
    {
        public int TongueLength { get; }

        public Frog(int tongueLength)
        {
            TongueLength = tongueLength;
        }
    }
}