Question

a windshield wiper blade is 17 in Long. Calculate the area come by the blade as it rotates through an angle of 138 degrees.​

Answer 1

Answer: 348 in²

Explanation:

Area of a circle is πr². Area of a sector is the same formula but only for the section so you need to determine what fraction of the circle it is. You do this by dividing by 360° if degrees are provided or by 2π if radians are given.

`A=\pi r^2 \bigg((\theta)/(360^o)\bigg)`

Given: r = 17

Ф = 138°

`A=\pi(17)^2\bigg((138^o)/(360^o)\bigg)\\\\\\.\quad =289\pi \bigg((23)/(60)\bigg)\\\\\\.\quad =(6647\pi)/(60)\pi\\\\\\.\quad =347.9\ in^2`