AREA OF A POLYGON                                                               
                                                                                
NUMBER OF VERTICES (ENTER 0 TO END PROGRAM)? 3                                  
COORDINATES OF VERTEX 1 ? 1,2                                                   
               VERTEX 2 ? 3,6                                                   
               VERTEX 3 ? 7,1                                                   
AREA = 13                                                                       
                                                                                
NUMBER OF VERTICES (ENTER 0 TO END PROGRAM)? 0                                  
