In figure A, B, and C are three points on a circle such that the angles subtended by the chords AB and AC at the centre O are 90∘ and 110∘ , respectively. Determine ∠ BAC.
OA= OB = Radius. (isosceles, triangle, base angles are equal.)
∠ OBA= ∠OMB = 45∘
Similarly :
OC = OA = Radius (isosceles triangle, base angles are equal.)
∠OAC = ∠OCA = (180∘ −110∘)2 = 35∘.
∠BAC = ∠BAO + ∠OAC = 80∘