Question

A helicopter's rotor sweeps out an area of 121 pi square

meters. What is the diameter of the rotor?

Answer 1

22 meters.

Explanation:

It's important to notice that the area is circular, which is defined by

`A= \pi r^(2)`

Replacing given values and solving for r, we have

`121 \pi = \ pi r^(2) \\121=r^(2)\\ r= √(121)=11`

But, the diameter is twice the radius, so

`d=2r=2(11)=22`

Therefore, the diameter is 22 meters.