error is - "first defined here" in simple Hierarchy classes - c++

Question

Im new in cpp, and tried to google the problame with no luck solving it, could use help.
Oh, and my files are all in the same folder.
the Rectangle.h file:
#ifndef RECTANGLE_H_
#define RECTANGLE_H_
#include "Polygon.h"
class Rectangle: public Polygon{
public:
Rectangle(int nColor);
Rectangle(Rectangle& r);
virtual string getType();
int getArea();
};
#endif /* RECTANGLE_H_ */
The errors are here, under each method signature it sais:
"first defined here"
the Rectangle.cpp file:
#include "Rectangle.h"
#include "Polygon.h"
//error is - "first defined here"
Rectangle::Rectangle(int color):Polygon(color, 3, "Rectangle"){
}
//error is - "first defined here"
Rectangle::Rectangle(Rectangle& r) :
Polygon(r) {
}
//error is - "first defined here"
string Rectangle::getType() {
return "Rectangle";
}
//error is - "first defined here"
int Rectangle::getArea() {
return 0;
}
I am also adding the father class "Polygon.h" but im pretty sure it's not relevant...
the only interesting thing about it is the method:
virtual string getType();
which is not abstract. just virtual
Polygon h:
#ifndef __POLYGON_H
#define __POLYGON_H
#include "Point.h"
#include <iostream>
#include <vector>
#include <string>
using namespace std;
class Polygon {
public:
Polygon(int nColor , int nPoints , std::string type);
Polygon(const Polygon &polyOther);
virtual ~Polygon() = 0;
int getColor();
virtual string getType();
void addPoint(Point* p);
Point* getPoint(int index) const;
int getNumOfPoints() const;
Polygon& operator=(const Polygon &polyOther);
private:
std::vector<Point*> _points;
const int _color;
string _type;
};
#endif
thanks for the help....