using c# code to use abstract and inheritance

//using c# code to use abstract and inheritance
sing System;
namespace OOPSProj
{
//code for inheritance
class Circle : Figure
{
public Circle(double radius)
{
base.radius = radius;
}
public override double GetArea()
{
return 3.14 * radius * radius;
}
static void Main()
{
Circle c = new Circle(45);
Console.WriteLine(c.GetArea());
Console.ReadLine();
}
}
}