I've passed this section, it wont accept answer and wont continue

namespace Treehouse.CodeChallenges
{
    class Square : Polygon
    {
        public double SideLength { get; private set; }

        public double Area => SideLength * SideLength;

        public Square(double sideLength) : base(4)
        {
            SideLength = sideLength;
        }

        public void Scale(double factor)
        {
            SideLength *= factor;
        }
    }
}

namespace Treehouse.CodeChallenges
{
    class Polygon
    {
        public int NumSides { get; private set; }

        public Polygon(int numSides)
        {
            NumSides = numSides;
        }
    }
}