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Homework Help: Geometry 3

  1. Jun 15, 2010 #1
    1. The problem statement, all variables and given/known data

    The diagram shows a box that has six faces .The top and bottom faces are square . THe other faces are all identical. What is the volume of the box ?

    2. Relevant equations

    3. The attempt at a solution

    Attached Files:

  2. jcsd
  3. Jun 15, 2010 #2
    What's your attempt so far? I.e. method and calculations? :smile:
  4. Jun 15, 2010 #3
    Hint: It is Pyramidal Frustum. Correct me if I am wrong.
  5. Jun 15, 2010 #4
    No that's what I was thinking too :wink: cheers njama on posting the link :smile:

    OK, so thereddevils give that a go now! :smile:
  6. Jun 16, 2010 #5
    ok so from the formula for volume of a pyramidal frustum is given by

    V=1/3(A1 + A2 + root(A1)(A2))(h)

    the height is root(18)

    A1=100 , A2=16

    i got V=220 cm^3

    but the answer given is 312 cm^3.
  7. Jun 16, 2010 #6


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    Homework Helper

    According to the diagram h = 6 cm.
  8. Jun 16, 2010 #7
    Yes the formula is:

    [tex]V=\frac{1}{3}h \left( A_{1}+A_{2}+\sqrt{A_{1}\times A_{2}} \right)[/tex]

    Where [itex]A_{1}[/itex] is the bottom area, [itex]A_{2}[/itex] is the top area, and [itex]h[/itex] is the height. Refer to your diagram for these values.

    If you check that you're using all of the correct values :wink: , then you'll get the answer.

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