In the figure, PQ and AB are respectively the arcs of two concentric circles of radii 7cm and 3.5cm and centre O. If ∠POQ = 300, then the area of the shaded region. [Use π=22/7]

PQ and AB are the arcs of two concentric circles of radii 7cm and 3.5cm respectively.
Let r1 and r2 be the radii of the outer and the inner circle respectively.
Suppose θ be the angle subtended by the arcs at the centre O.
Then r1 = 7cm, r2 = 3.5cm and θ = 30°
Area of the shaded region = Area of sector OPQ - Area of sector OAB
= θ/360° πr1² - θ/360° πr2²
= θ/360° π (r1² - r2²)
= 30°/360° × 22/7 [7² - 3.5²]
= 1/12 × 22/7 × (49 - 12.25)
= 1/12 × 22/7 × 36.75
= 9.625
Therefore, the area of the shaded region is 9.625cm².