Page 2 - EXERCISE 7.3
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MAHEISHANG                                                                                                                CLASS IX BOSEM
               BOOKS AND TUTORIAL

                               
                lets assumed in  ABC
                we will used exterior angle property 

                   
                In  AQB,
                   AQC    ABQ  ex angle is greater than one of its opp angle 
                 
                . i e AB>AQ   eqn 1

                   
                In  BRC,
                                 
                         
                 
                                                                          le
                   BRA> BCR   ex angle is greater than one of its opp ang 
                i.e BC>BR    eqn 2
                   
                In  CPA
                 
                         
                   CPB> CAP     ex angle is greater than one of its opp angle 
                i.e CA>CP    eqn 3
                adding eqn 1 ,eqn 2 and eqn 3 ,we get
                AB+BC+CA>AQ+BR+CP    h/p


               Q4.Show that the difference of any two sides of a triangle is less than the third side.

                soln:
                construction :  C on AD and joined BC
                to prove:   AB-BD<AD or BD-AD<AB or AD-AB<BD

                proof:
                    5   2              exterior angle is greater than one of the opp angle
                 i.e  AC<BD    eqn 1
                     
                 
                   6< 5               exterior angle is greater than one of the opp angle
                . i e  CD<AB  eqn 2
                adding eqn 1 and eqn 2,we get
                     AC+CD<BD+AB
                            
                  AD   BD AB
                      
                  AD AB     BD   h/p
















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