Question

Ubehebe Crater in Death Valley has a diameter of a little more

than 1
−
2
mile. If Latisha walks around its rim at a rate of 2 miles per hour,
about how long will it take her to walk all the way around the crater?
Find your answer to the nearest tenth. Use 3.14 for π.

Answer 1

First, we are going to use the formula of the circumference of a circle:
`C=2 \pi r`
where

`C` is the circumference of the circle.

`r` is the radius of the circle.

We know for our problem that the diameter of Ubehebe Crater is 1 mile. Since the radius of a circle is half its diameter, the radius of our crater will be:
`r= (1)/(2) =0.5`. Lets replace that value in our formula:

`C=2 \pi r`

`C=2*3.14*0.5`

`C=3.14` miles

Next, we are going to use the distance speed time formula:
`t= (d)/(s)`
where

`t` is time

`d` is distance

`s` is speed

We know for our problem that Latisha walks around its rim at a rate of 2 miles per hour, so her speed is 2 mph; therefore,
`s=2`. We also know for our previous calculation that the circumference of the crater is 3.14 miles, so
`d=3.14`. Lets replace those values in our formula to find
`t`:

`t= (d)/(s)`

`t= (3.14)/(2)`

`t=1.6` hours

We can conclude that it will take Latisha 1.6 hours to walk all the way around the crater.