question_answer

P, Q and R are the centres and \[{{r}_{1}},\,\,{{r}_{2}},\,\,{{r}_{3}}\] are the radii respectively of three co-axial circles, then \[QRr_{1}^{2}+RP\,r_{2}^{2}+PQr_{3}^{2}\] is equal to

A)            \[PQ\ .\,QR\,.\,RP\]                   

B)          \[-PQ\,.\,QR\,.\,RP\]

C)            \[P{{Q}^{2}}.Q{{R}^{2}}.R{{P}^{2}}\]                        

D)            None of these