Cubical Block

Discussion in 'Basic Math' started by nycmathguy, Aug 30, 2021.

  1. nycmathguy

    nycmathguy

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    A cubical block of metal weighs 6 pounds. How much will another cube of the same metal weigh if its sides are twice as long?

    Let me see. Everything I am about to do is my guess. This problem is not clear to me.

    A cube has 6 sides.

    6 /w = 6/12

    6w = 6(12)

    6w = 72

    w = 72/6

    w = 12 pounds

    You say?
     
    nycmathguy, Aug 30, 2021
    #1
  2. nycmathguy

    MathLover1

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    If the original cube weighs 6 pounds and you double the sides of the cube, then you double in three directions, so you now have 8 of the original cubes.
    Hence the weight of the new cube is 8*6=48 pounds.

    or this way, compare the volumes
    if side is a
    V=a^3
    if side a doubles, we have 2a
    then V=(2a)^3=8a^3

    the weight of the new cube is 8 times more

    8*6=48 pounds
    upload_2021-8-30_21-44-6.gif
     
    MathLover1, Aug 31, 2021
    #2
    HallsofIvy and nycmathguy like this.
  3. nycmathguy

    nycmathguy

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    Ok. I tried. You will see exactly how weak I am at solving applications. This is my main struggle---word problems.
     
    nycmathguy, Aug 31, 2021
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  4. nycmathguy

    HallsofIvy

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    You seem to have assume that this was a hollow block so that only the sides have weight, not the interior.
     
    HallsofIvy, Nov 21, 2021
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  5. nycmathguy

    nycmathguy

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    Brother, I never assume. I always do my best. If I start to assume, then I will make an ass of u and me. Get it?
     
    nycmathguy, Nov 21, 2021
    #5
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