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Mathematics
Mathematics
Problem
In a
△
A
B
C
\triangle ABC
△
A
B
C
, the side AB and AC are produced to P and Q respectively. The bisector of
∠
P
B
C
\angle PBC
∠
P
B
C
and
∠
Q
C
B
\angle QCB
∠
QC
B
intersect at a point O. Prove that
∠
B
O
C
=
90
∘
−
1
2
∠
A
\angle BOC = 90^\circ - \frac{1}{2} \angle A
∠
B
O
C
=
9
0
∘
−
2
1
∠
A
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