Windshield wiper problem :(

Question

The rear windshield wiper blade on a car has a length of 11 inches. The blade is mounted on a 15 inch arm, 4 inches from the pivot point. If the wiper turns through an angle of 110 degrees, how much area is swept clean?

Answer 1

110° = 110π/180 = 11π/18 Area of sector = (1/2)r²θ, where r = radius and θ = radian measure of the central angle.

Area = (1/2)(15)²(11π/18) - (1/2)(4)²(11π/18)