# Thread: a couple of word problems

1. ## a couple of word problems

A circular coffee table has a diameter of 5 ft. What will it cost to have the
top refinished if the company charges $3 per square foot the refinishing? The distant from Philadelphia to Sea Isle City is 100 mi. A car was driven distance using tires with a radius of 14 in. How many revolutions of each tired occurred on the trip? Can you please show me how you came up with the answer to these story problems? 2. Originally Posted by Patience A circular coffee table has a diameter of 5 ft. What will it cost to have the top refinished if the company charges$3 per square foot the refinishing?
The area of the table top is $\displaystyle \pi r^2$, and here $\displaystyle r=2.5 \mbox(ft)$ (half the diameter), so the area is $\displaystyle \pi \times 2.5^2 \approx 19.6 \mbox{sq ft}$. So the cost is $\displaystyle \$ 3 \times 19.6=\$58.80$

The distant from Philadelphia to Sea Isle City is 100 mi. A car was driven distance using tires with a radius of 14 in. How many revolutions of each tired occurred on the trip?
1 mile is 5280 feet, so 100 miles is 528000 feet.

The circumference of the tires is $\displaystyle 2\,\pi\,r$, so in this case the circumference is ~87.96 inches or ~7.33 feet. So in moving 7.33 feet the tire rotates once.

So in travelling 100 miles each tire will revolve 528000/7.33~72033 times.

RonL