Geometry, 4th ed. Ch.3 pg 49 #10

[futjim]

Dear all,

I had trouble with the following question. Can anyone help?

10) A rectangular box has the dimensions 12 inches x 10 inches x 8 inches. What is the largest possible volume of a right cylinder that is placed inside the box?

I did 2 trials:
1) r = 6, h = 10
2) r = 5, h = 12

Why are these invalid test subjects?

[phoenix.rkchr]

This will be easy if you imagine the box.

Your both trials are incorrect:
1) r = 6, h = 10
In this case, you are taking 12 X 8 as base of the box and 12 as height. If radius of cylinder = 6 then diameter will be 12. Now how the cylinder with diameter of size 12 will be fit in 12 X 8 base? To accommodate the cylinder with radius 6 you need at least box base of size 12 X 12.

2) r = 5, h = 12
Same logic applicable here.

So you need to consider height = 8.

Hope this clears your doubt.

[tim]

thanks, phoenix..

[abedinbhuiyan]

That's how GMAC confuses test takers!!!

BR

[tim]

indeed..