Using Polymorphism in C++ program

#include <iostream>
using namespace std;
class Rectangle{
      public:
             double height;
             double width;
             double Rect(double height, double width)
             {
                      return height*width;
             }
};
class Triangle: public Rectangle{
      public:
             double trig(double height, double width)
             {
                 return height*width*0.5;
             }
};
int main()
{
    Rectangle Rec;
    Triangle Tri;
    Rec.height=8;
    Rec.width=7;
    Tri.height=8;
    Tri.width=7;
    cout<<Rec.Rect(Rec.height,Rec.width)<<endl;
    cout<<Rec.Rect(6,5)<<endl;
    cout<<Tri.trig(Tri.height,Tri.width)<<endl;
    cout<<Tri.trig(6,5)<<endl;
    system("pause");
    return 0;
}
    

The output is given below:

56
30
28
15