面积和面积周长输出相同

Question

public class Circle : Shape
{
    private float perimeter, area;

    public override float getPerimeter(float Dimension)
    {
        perimeter = (float)(2 * Math.PI) * (Dimension / 2);
        return perimeter;
    }

    public override float getArea(float Dimension)
    {
        area = (float)Math.PI * ((Dimension / 2) * (Dimension / 2));
        return area;
    }

}

public class Square : Shape
{
    private float perimeter, area;

    public override float getPerimeter(float Dimension)
    {
        perimeter = (float)(Dimension * 4);
        return perimeter;
    }

    public override float getArea(float Dimension)
    {
        area = (float)(Dimension * Dimension);
        return area;
    }

}

这只是抽象类，但在运行程序时似乎存在问题：Area和Perimeter输出都是相同的，我不知道为什么。