Question

If a circle takes 8 rotations to roll 5 meters, what is its radius?

Answer 1

8 full rotations measures 5 meters.
That means 8 times the circumference is 5 meters.

Let C = circumference.

8C = 5

C = 5/8 = 0.625

The circumference measures 0.625 m.

The circumference is


`C = 2 \pi r`

Now we substitute our value into the circumference formula.


`0.625 = 2 \pi r`


`2 \pi r = 0.625`


`\pi r= 0.3125`


`r = (0.3125)/(\pi)`


`r \approx 0.09947`


`r \approx 0.1 ~m`