SOLUTION: Similar pyramids have altitudes of 3cm and 4cm. The volume of the smaller pyramid is 30cm^3. What is the volume of the larger pyramid?

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Question 1177847: Similar pyramids have altitudes of 3cm and 4cm. The
volume of the smaller pyramid is 30cm^3. What is the
volume of the larger pyramid?
Found 2 solutions by MathLover1, ikleyn:
Answer by MathLover1(20850)   (Show Source): You can put this solution on YOUR website!

the ratio of altitudes:
since pyramids are similar, volumes are proportional in same ratio of altitudes:





the volume of the larger pyramid is



Answer by ikleyn(52786)   (Show Source): You can put this solution on YOUR website!
.

            The solution and the answer in the post by  @MathLover1 are both  ABSOLUTELY  WRONG.

            I came to bring a correct solution. 


For similar 3D solids, the ratio of their volumes is the cube of the ratio of their respective linear dimensions.


Since in this problem the ratio of linear dimensions is  ,  the ratio of their volumes is  .


Therefore, the volume of the larger pyramid is   =  = 213   cm^3.



ANSWER.  The larger pyramid volume is   213    cm^3.

Solved   (correctly).

------------

For your safety,  ignore the post by  @MathLover1.


////////////


Looking into her activity in last several days, I start thinking that

@MathLover1 presents a real danger for any visitor to this forum, because she provides wrong solutions even to simplest Math problems.


See my notes to her posts in past two days

https://www.algebra.com/algebra/homework/Finance/Finance.faq.question.1177850.html

https://www.algebra.com/algebra/homework/Volume/Volume.faq.question.1177847.html

https://www.algebra.com/algebra/homework/Surface-area/Surface-area.faq.question.1177846.html

https://www.algebra.com/algebra/homework/Triangles/Triangles.faq.question.1177800.html

https://www.algebra.com/algebra/homework/Triangles/Triangles.faq.question.1177804.html



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