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Homework Help: Surface area of a sphere problem

  1. Sep 7, 2005 #1
    Sphere 1 has surface area A1 and volume V1, and shere 2 has surface area A2 and volume V2.
    If the radius of shere 2 is four times the radius of shere 1, what is the ratio A2/A1 of the areas?
     
  2. jcsd
  3. Sep 8, 2005 #2

    mukundpa

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    Homework Helper

    Surface area of a sphere is 4 Pi R^2 and R2 = 4R1
     
  4. Sep 8, 2005 #3
    thank you
    and i have 1 more question,
    what is the ratio V2/V1 of the volumes?
     
  5. Sep 8, 2005 #4


    V1= 4/3 Π R1^3

    V2= 4/3 Π R2^3

    Π= PI

    DIVIDE BOTH EQUATIONS:

    V1= 4/3 Π R1^3
    V2= 4/3 Π R2^3

    SINCE: R2= 4R1 THEN

    V1= 4/3 Π R1^3
    V2= 4/3 Π (4R1)^3

    V1= 4/3 Π R1^3
    V2= 4/3 Π*64*R1^3

    CANCEL (4/3, PI & R1^3)

    THEREFORE:

    V1= 1_
    V2= 64

    OR V2/V1= 64
     
    Last edited: Sep 8, 2005
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