Question

What is the approximate diameter of a tire that will make 775 complete rotations in one mile? (Note: there are 5280 feet

in 1 mile)

Answer 1

About 2.17 feet.

Explanation:

Let d represent the diameter of the tire.

Then the circumference of the tire will be:

`C=d\pi`

So, the tire will travel dπ miles after one rotation.

After 775 rotations, the total miles traveled should be 5280 feet. Thus:

`775(d\pi)=5280`

Solve for d:

`\displaystyle d=(5280)/(775\pi)`

Approximate:

`d=2.1686...\approx2.17`

The circumference of the tire should be about 2.17 feet.