In the given figure, chords AB=CD, ∠COD=60∘, and ∠AOD=170∘.
Find the value of ∠BOC.
We know that equal chords of a circle subtend equal angles at the centre.
⇒∠AOB=∠COD=60∘
Since, the central angle of a circle is 360∘.
So, ∠AOB+∠BOC+∠COD+∠AOD=360∘
⇒60∘ +∠BOC+60∘ +170∘ =360∘
⇒290∘ +∠BOC=360∘
⇒∠BOC=360∘ −290∘ =70∘