SOLUTION: The volume of a cone varies jointly as the height and the square of the radius of the base. A cone height 8 cm and a base of diameter 9 cm has volume 54π. Find the constant of

Algebra ->  Probability-and-statistics -> SOLUTION: The volume of a cone varies jointly as the height and the square of the radius of the base. A cone height 8 cm and a base of diameter 9 cm has volume 54π. Find the constant of      Log On


   



Question 196976This question is from textbook algebra and trigonometry
: The volume of a cone varies jointly as the height and the square of the radius of the base. A cone height 8 cm and a base of diameter 9 cm has volume 54π. Find the constant of variation and use it to develop the general formula for the volume of a cone. This question is from textbook algebra and trigonometry

Found 2 solutions by solver91311, stanbon:
Answer by solver91311(24713) About Me  (Show Source):
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The volume varies jointly as the height and the square of the radius of the base means:



You are given that the volume is when the height is 8 and the diameter is 9. The diameter being 9 means that the radius is 4.5, so:




where is the constant of proportionality. Solve the above equation for and replace in the first equation with that value. (Hint: Leave it in terms of )


John


Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
The volume of a cone varies jointly as the height and the square of the radius of the base.
V = k[h*r^2]
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A cone height 8 cm and a base of diameter 9 cm has volume 54π. Find the constant of variation and use it to develop the general formula for the volume of a cone.

54 = k[8*(9/2)^2]
54 = k[162]
k = 54/162
k = 1/3
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Equation:
V = (1/3)h*r^2
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Cheers,
Stan H.
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