In Figure, there are shown sectors of two concentric circles of radii 7cm and 3.5cm. Find the area of the shaded region. (Use `pi=(22)/7`).

Explanation

Given : `theta=30^0`

Area of the shaded region = Area of sector having radius 7cm - Area of sector having radius 3.5cm

`:.`Area of the shaded region = ` ((30^0)/(360^0)) xx 22/7xx 7^2 - ((30^0)/(360^0)) xx 22/7xx (3.5)^2 `

`:.`Area of the shaded region =` (77)/6 - (77)/(24)=9.625 cm^2`