In $$\triangle ABC$$, the external bisectors of the angles $$\angle B$$ and $$\angle C$$ meet at the point O. If $$\angle A=70^\circ$$, then the measure of $$\angle BOC$$ is:
Given : O is excentre of $$\triangle$$ ABC and $$\angle A=70^\circ$$
To find : $$\angle$$ BOC = $$\theta=?$$
Solution : Excentre of a triangle = $$90^\circ-\frac{1}{2} \times $$ (Angle opposite to it)
=> $$\theta=90^\circ-\frac{\angle A}{2}$$
=> $$\theta=90^\circ-\frac{70^\circ}{2}$$
=> $$\theta=90^\circ-35^\circ=55^\circ$$
=> Ans - (D)
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