Hollymae764
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#1
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Why is the surface area
2xh + 8 xh +4x^2 = 1728

not 4xh +16xh+8x^2 = 1728 if there is no top of the box, would the inside also increase the surface area?
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RDKGames
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(Original post by Hollymae764)
Why is the surface area
2xh + 8 xh +4x^2 = 1728

not 4xh +16xh+8x^2 = 1728 if there is no top of the box, would the inside also increase the surface area?
Why do you think it is 4xh instead of 2xh?

There are two sides of area x*h

There are two sides of area 4x*h

There is one side of area 4x*x
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Hollymae764
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(Original post by RDKGames)
Why do you think it is 4xh instead of 2xh?

There are two sides of area x*h

There are two sides of area 4x*h

There is one side of area 4x*x
But if the box has no lid why do you not count the other side. So for the bottom of the cuboid, 4x^2 one side and 4x^2 the other
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RDKGames
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(Original post by Hollymae764)
But if the box has no lid why do you not count the other side. So for the bottom of the cuboid, 4x^2 one side and 4x^2 the other
Not sure what you mean.

Why don't you just draw a net of the cuboid and label each area, and add them up?
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Hollymae764
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(Original post by RDKGames)
Not sure what you mean.

Why don't you just draw a net of the cuboid and label each area, and add them up?
but thats only the area of one side, like if you have a square piece of paper with lengths 4 x 4 one side will have an area of 16 but if you flip the paper over the other side will also have an area of 16 so total as is 32
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RDKGames
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(Original post by Hollymae764)
but thats only the area of one side, like if you have a square piece of paper with lengths 4 x 4 one side will have an area of 16 but if you flip the paper over the other side will also have an area of 16 so total as is 32
You dont need to care about the area on the other side of the "wall"
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davros
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(Original post by RDKGames)
You dont need to care about the area on the other side of the "wall"
Not sure where this question is taken from, but should it not really say "external surface area" if that's what it means?

I think it's easy to misinterpret what's required here, unless it's a case of over-thinking
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RDKGames
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(Original post by davros)
Not sure where this question is taken from, but should it not really say "external surface area" if that's what it means?

I think it's easy to misinterpret what's required here, unless it's a case of over-thinking
Yes it should be 'external' area.

Yesterday, with a student of mine, I came across a mechanics question from one of Madas' hard papers. He made a typo in the question itself, so I suspect this is just another unfortunate wording issue.
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Hollymae764
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(Original post by RDKGames)
Yes it should be 'external' area.

Yesterday, with a student of mine, I came across a mechanics question from one of Madas' hard papers. He made a typo in the question itself, so I suspect this is just another unfortunate wording issue.
Oh thank you
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