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Hi friends,

 

a most ridicilous question in my opinion..

 

A lead cast in the shape of a cone with a base diameter of 210mm and a perpendicularf height of 110mm is melted and recast in the shape of a sphere....

 

WHY ON EARTH could they just not say...A sphere with dimentions this and that...surely we cannot use these dimentions for the sphere?They want tyhe diameter and surface area...

 

I am thinking about this logically....surely the diameter of the sphere will and can never be 210mm?

 Oct 25, 2020
 #1
avatar+111546 
+1

A lead cast in the shape of a cone with a base diameter of 210mm and a perpendicular height of 110mm

is melted and recast in the shape of a sphere....

 

You need to find the VOLUME of the cone first.    

Can you do that please ?

 Oct 25, 2020
 #2
avatar+781 
+1

Oookay... I can see your angle... I think Ill be able to crack this one... Melody!!... Thank you kindly.. 

juriemagic  Oct 25, 2020
 #3
avatar+111546 
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That is great. 

Give it a go and come back and ask for more help if you need it. 

Don't forget to explain what you have tried though.    laugh

Melody  Oct 25, 2020
 #4
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+1

 

WHY ON EARTH could they just not say...     

 

Jurie, the point of this – indeed, of math questions in general – is to train your mind to think logically.  In this example, you must work the formula (for the volume of a cone) forward to obtain the volume (amount of lead) of the cone, then work the formula (for the volume of a sphere) backward to obtain the radius of the sphere. 

.

 Oct 25, 2020
 #5
avatar+111546 
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Yep,

Guest has given you a very good answer Juriemagic.

Thanks Guest.

Melody  Oct 25, 2020
 #6
avatar+781 
+1

Hi guest,

 

absolutely correct, all of this came to me as well the moment I saw the "hint" from Melody to calculate the volume. I immediately understood things that way. I also explained precisely this to my student, the questions are formulated in this way sometimes, to cause you to think out of the box. Thank you for sharing!

juriemagic  Oct 27, 2020

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