OAB is an equilateral Triangle with side 12 Circle with radius of 6
Each angle of an equilateral triangle is 60°
Angle at the centre in segment, θ = 60°
Area of Major segment + Area of an equilateral triangle OAB
= 94.28 + 36 × 1.73
= 94.28 + 62.28
= 156.56 sq. cm.