Every 24 hours, Earth makes a full rotation around its axis. Earth's speed of rotation at the equator is 1,670 km per hour. What is the circumference of Earth's equator?

(Hint: Earth's circumference at the equator is equal to the distance that Earth rotates around the equator).

 Apr 7, 2019

Well if the circumfrence is equal to a complete rotaion than all that is required is to melitply 1,670 x 24 like this. 




\(1,670\times 24 = product\) 


\(product = circumfrance\) 



Do correct me though if I miss interpeted the problem.


 Apr 7, 2019


Sometimes it helps to cancel units.  You can cancel units the same as you cancel numbers. 


Example:  1670 km/hour x 24 hour/1 =

I just put hour over 1 to make it obvious that hour is a numerator in that term.

Cancel the hour in the denominator of km/hour and the hour in the numerator:  km/hour x hour/1 = km/1 or simply km

And it's just arithmetic to multiply the numbers 1670 x 24


That's going to come to approximately 40,000 because 24 is almost (100 x 1/4) and (1/4 x 1670) is close to 400

You should multiply them on out formally and get the exact answer.


 Apr 8, 2019

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