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volume ratio math Q

Discussion in 'DAT Discussions' started by tRNA, May 13, 2007.

  1. tRNA

    tRNA Member 10+ Year Member

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    Apr 28, 2005
    diameter of sun=864000miles, diameter of earth=8000miles find the approximate ratio of the volume of the sun to the volume of earth?
    answer= 1250,000:1

    i don't understand what's wrong with my method, why am i not getting the right answer?? this is how i did it

    1)vol. of sphere= 4(pi)r^3/3
    2) r for sun=432000, earth=4000

    3) (4pi(432000)^3/3)/(4pi(4000)^3/3)
    4) cancel the 4pi/3 from the top and bottom so your left with
    (432000)^3/(4000)^3 which is the same as:
    (432000)(432000)(432000)/(4000)(4000)(4000)
    5) then after canceling everything you get (18)^3/(1)^3 which is 5832:1
     
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  3. tRNA

    tRNA Member 10+ Year Member

    280
    0
    Apr 28, 2005
    I understand how they got their answer but what's wrong with the above method???
     
  4. doc toothache

    doc toothache 10+ Year Member

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    2,052
    Jan 17, 2006
    It is your math. 432000/4000=108 not 18.
     

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