Question 760033: Can you please help me answer this question? The wheels of a car have a radius 11inches and are rotating at 600 revolution per minute. Find the speed of the car in mi/hr.
Answer by KMST(5328)   (Show Source):
You can put this solution on YOUR website! The circumference of a circle can be calculated as  .
Using the approximation  , the circumference of each of those wheels is calculated as
 inches.
That is how much the car advances as the wheels turn one turn.
In one minute, the wheels go through  turns, so the car advances
 inches
There are  inches in  foot, so that is
 feet.
There are  feet in mile, so that is
 = approximately  miles.
So, in one minute, the car advances miles,
and since there are  minutes in hour, the car's speed is
 = approximately 
Writing all the calculations together, we look so much smarter:
 = approximately
If the teacher expects it, you can write it with the units, as above.
Otherwise, you can write something like
and you can enter all that into a calculator at once as:
2 X 3.14 X 11 X 600 X 60 ÷ 12 ÷ 5280 = 39.25
or as
2 X 3.14 X 11 X 600 X 60 ÷ (12 X 5280) = 39.25
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