Question

AB and CD are arcs of two concentric circles of radii 21 cm and 7 cm respectively and centre O. If ∠AOB = 30°, find the area of the shaded region.

Answer 1

Area of the shaded region

= Area of sector AOB – Area of sector COD

Area of sector AOB

Here, radius = 21cm and θ = 30°

Area of sector COD

Here, radius = 7cm and θ = 30°

Now, shaded region = Area of sector AOB – Area of sector COD