Question 1149570:  The weight W of a cylindrical metal varies jointly as its legth l and the square of the diameter d of its base. 
If W=6kg when l=6cm and d=3 cm,find the equation of variation 
 Found 2 solutions by  josgarithmetic, ikleyn: Answer by josgarithmetic(39630)      (Show Source):  Answer by ikleyn(52903)      (Show Source): 
You can  put this solution on YOUR website! . 
The weight W of a cylindrical metal varies jointly as its legth l and the square of the diameter d of its base. 
If W=6kg when l=6cm and d=3 cm,find the equation of variation 
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From the problem's description
    W =  ,    (1)
where  L is the length and d is the diameter, and "k" is the constant value coefficient.
From equation (1),  
    k =   =   = 0.111111... 
Then the equation (1) takes the form
    w =  .
It is the equation you are asking for.
 
 
        Be aware : The equation and the value of  "k",  found by @josgatithmetic in his post, 
 
        are   W R O N G,   so you better simply  IGNORE  it/them for your safety.
 
 
 
There is another circumstance I want to aware you.
The coefficient  "k"  divided by  , i.e.    =   = 0.1414 kilograms per cm^3 = 141.4 grams per cm^3.
This ratio     in this problem, is nothing else as the specific weight (or density) of the metal.
The fact is that THERE IS NO such a heavy metal on the Earth.  The heaviest is osmium  with the specific weight (density) of 22.6 g/cm^3
 
 
 
So,  the entire your problem is  a    F A K E,  and you better throw it into the  GARBAGE BOX --- the only right place for it . . . 
 
 
 
 
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