Question

The circumcentre of the triangle AABC is O. Prove that ZOBC + ZBAC = 90°​

Answer 1

Answer:

O is circumcentre of ΔABC, join OB and OC. We know that

∴∠BOC=2∠BAC

z=2x

In ΔOBC

∠OBC+∠OCB+∠BOC=180

y+z+y=180

2y+z=180  

2y+2x=180

2(x+y)=180

x+y=90

∠BAC+∠OBC=90

or ∠OBC+∠BAC=90

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