The exterior angles B and C in ΔABC are bisected to meet at a point P. (i) Is ∠BPC=90o−A2? (ii) Is ABPC a cyclic quadrilateral ?
A
(i) No. (ii) Yes
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
(i) Yes . (ii) No.
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
C
(i) No (ii) Can't be determined.
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
(i) Can't be determined. (ii) No.
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution
The correct option is B (i) Yes . (ii) No. Given−ΔABChasitsexternalangles∠CBR&∠BCQbisectedbythelinesBP&CPrespectively.BP&CPintersectatP.Tofindout−(i)is∠BPC=90o−A2?(ii)isABPCacyclicquadrilateral?Solution−∠PBC=∠PBR⟹∠PBC+∠PBR=2∠PBC.So∠ABC+2∠PBC=180o(linearpair).i.e∠PBC=90o−∠ABC2........(i).Similarly∠PCQ=∠PCB⟹∠PCB+∠PCQ=2∠PCB.So∠ACB+2∠PCB=180o(linearpair).i.e∠PCB=90o−∠ACB2........(ii).Adding(i)&(ii)wehave∠PBC+∠PCB=90o−∠ABC2+90o−∠ACB2=180o−12(∠ABC+∠ACB)⟹180o−∠BPC=180o−12{180o−∠BAC}⟹∠BPC=90o−BAC2.......(ans−i).AgainthesumoftheoppositeanglesofthequadrilateralABPC=∠BAC+∠BPC=∠BAC+90o−BAC2≠180o.∴ThequadrilateralABPCisnotacyclicquadrilateral.........(ans−ii).(∵thesumoftheoppositeanglesofacyclicquadrilateral=180o).Ans−OptionB.