An automobile windshield wiper 7 inches long rotates through an angle of 60 ∘ . If the rubber part of the blade covers only the last 6 inches of the wiper, find the area of the windshield cleaned by the windshield wiper.

25.13 square inch

Step-by-step explanation:

The automobile windshield wiper 7 inches long rotates through an angle of 60 degrees.

Note that the rubber part covers only the last 6 inches of the wiper.

To find the area of the windshield cleaned by the wiper,

We find the area of the annulus shaded in grey in the diagram.

Area of a Sector=

For the larger sector, Radius, R=7cm

For the smaller Sector, radius r=1cm

Area cleaned by the wiper

The area cleaned by the wiper is 25.13 square inch.