Question

A windshield wiper turns through an angle of 150°. The top of the blade traces the are with a 20-inch radius. How long is the

arc?
A. 52.36 inches
B. 75.4 inches
C. 0.1308 inches
D. 3000 inches

Answer 1

A

Explanation:

Arc length is given by the formula:

`\displaystyle s=2\pi r(\theta)/(360^\circ)`

Where r is the radius and θ is the central angle, in degrees.

The windshield wiper has a radius of 20 inches and a central angle of 150°. Hence:

`\displaystyle s=2\pi (20)\left((150)/(360)\right)`

Use a calculator:

`\displaystyle s=(50)/(3)\pi \approx52.36\text{ inches}`

Our answer is A.