The correct answer is (A):
It is given that radius of the circle = 1 cm
Chord AB subtends an angle of 60° on the centre of the given circle. R be the region bounded by the radii OA, OB and the arc AB.
Therefore, R = 60°/360°×Area of the circle = 1/6×π×(1)2 = π/6 sq.cm
It is given that OC = OD and area of triangle OCD is half that of R. Let OC = OD = x.
Area of triangle COD = 1/2×OC×OD×sin60°
π/6×2 = 1/2×x×x×√3/2
⇒ x2 = π/3√3
⇒ x = (π/3√3)1/2 cm.