Q) A car has two wipers which do not overlap. Each wiper has a blade of length 21 cm sweeping through an angle of 120°. Find the total area cleaned at each sweep of the two blades.
Ans:
Area cleaned by a blade = π r2 
= 
x 21 x 21 x 
= x 21 x 21 x 
= 22 x 21
= 462 cm2
The area cleaned by 2 blades:
= 462 x 2
= 924 cm2
Therefore, the area cleaned by two blades = 924 cm2