Question

A roundabout is a one-way circular intersection.

About how many feet would a car travel if it drove
once around the roundabout? Round to the
nearest foot.

Answer 1

`471\:\mathrm{ft}`

Explanation:

In one full rotation around the roundabout, the car is travelling a distance equal to the circumference, or the perimeter, of the circle. The circumference of a circle with radius
`r` is given by
`C=2r\pi`. In the diagram, the diameter is labelled 150 feet. By definition, the radius of a circle is exactly half of the diameter of the circle. Therefore, the radius must be
`(150)/(2)=75` feet. Thus, the car would travel
`2\cdot 75\cdot \pi=471.238898038=\boxed{471\:\mathrm{ft}}`