Find the area of the shaded region in Fig. 12.20, if radii of the two concentric circles with centre O are 7 cm and 14 cm respectively and ∠ AOC = 40°.

Area of the shaded region = Area of Bigger sector –area of Smaller Sector

If R and r are the two radii of Bigger and Smaller circles respectively, then:

Area of shaded region = ²² )

= ²² )

= 51.33 sq cm