Answers

2016-03-03T18:48:28+05:30
∠OBC =  ∠OCB ........opposite angles of equal sides in ΔBOC
∠BOC + ∠OBC + ∠OCB = 180'
2∠BOC + ∠BAC = 180
2∠OBC + 2∠BAC = 180
2(∠OBC + ∠BAC) = 180
∠OBC + ∠BAC = 90'
 
I hope it helps........ 


2 4 2
2016-03-05T23:05:48+05:30
Given that from the above ∠obc = ∠ocb
the opposite sides of equal side in Δboc
∠boc+∠obc+∠ocb = 180
2∠boc + ∠bac = 180
2∠obc+2∠bac = 180
2(∠obc+∠bac) = 2(90)
∠obc+∠bac = 90
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