Ask about protected keyword

Please help me. I read many books and they talk: protected member can be accessed from member in same class, friend of own class, derivative class and friend of derivative class. I write code on codeblocks, all things are right, but friend of derivative class is wrong. Why ? Please help me. Here's my code
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Code:

class Polygon{
    protected:
        int w, h;
    public:
        void setValue(int w, int h){
            this->w = w;
            this->h = h;
        }
};
class Rectangle:public Polygon{
    public:
        int area(){
            return w*h;
        }
    friend int area1();
};

int area1(){
    return w*w;
}

 

What is "w" here?? w is not recognized..pass the object of Rectangle in area1 and then access "w" ...