As the incentre is formed by joining angle bisectors of ∠A, ∠B and ∠C of a triangle ABC,
∴ In ΔOBC,
By Angle Sum Property,
∠BOC + ½ ∠ABC + ½ ∠ACB = 180°
⇒ ½ (∠ABC + ∠ACB) = 180° – 110° = 70°
⇒ ∠ABC + ∠ACB = 140° ---(1)
In ΔABC,
By Angle Sum Property,
∠BAC + ∠ABC + ∠ACB = 180°
From 1,
∠BAC + 140° = 180°
∴ ∠BAC = 40°.