a couple of word problems

• Dec 13th 2006, 08:45 PM
Patience
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? • Dec 13th 2006, 11:50 PM CaptainBlack Quote: 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 $\pi r^2$, and here $r=2.5 \mbox(ft)$ (half the diameter), so the area is $\pi \times 2.5^2 \approx 19.6 \mbox{sq ft}$. So the cost is $\ 3 \times 19.6=\58.80$

Quote:

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 $2\,\pi\,r$, 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