View Full Version : A question about surface area

elcatracho

08-18-2005, 01:38 PM

This question is very hard for me because it does not deal with actual numbers, rather is deals with variables.

The question is... Find the surface area of a box of height h whose base dimensions are p and q and that satisfies the following condition

question A- The box is closed

Question B- The box has an open top

Question C- The box has an open top and a square base

I'd be really thankful for some assitance on this question. Thanks, Luis

tkhunny

08-18-2005, 02:01 PM

This question is very hard for me because it does not deal with actual numbers, rather is deals with variables.

The question is... Find the surface area of a box of height h whose base dimensions are p and q and that satisfies the following condition

question A- The box is closed

Question B- The box has an open top

Question C- The box has an open top and a square base

I'd be really thankful for some assitance on this question. Thanks, LuisWhy does it make any difference? The concept of substitution is very, very VERY important. If x = 2, does it matter if you write 2 or x? No. They are the same.

How would you work this problem? Just set it up. Don't solve it.

Find the surface area of a box of height 12 in whose base dimensions are 6 in and 9 in and that satisfies the following condition

question A- The box is closed

Question B- The box has an open top

Question C- The box has an open top and a square base

I'll do the first one. Top and bottom are the same, 2*6*9. Two sides match, 2*6*12. The other two sides also match, 2*9*12.

elcatracho

08-19-2005, 11:39 PM

I understand the first part because it follows the Surface area formula... the problem that i'm running into is the fact that i don't understand how having the top open will affect the surface area. Will it just be adding another p*q because their is an additional space that is exposed and that would be it's area. And for step three how would I be able to express that the bottom is a sqaure? by simply stating that p=q? I think I have an idea of how to solve it but i'm still a bit confused. Thanks, Luis

Denis

08-20-2005, 12:42 AM

I understand the first part because it follows the Surface area formula... the problem that i'm running into is the fact that i don't understand how having the top open will affect the surface area. Will it just be adding another p*q because their is an additional space that is exposed and that would be it's area.

C'mon Luis...THINK!

A box with a top has 6 "surfaces", the top being one (equal to bottom);

a box with no top has 5 surfaces...THERE'S NO TOP!

elcatracho

08-21-2005, 11:13 PM

I'm still confused because wouldn't a box with an OPEN top have seven sides since there is a new side exposed. WOuld u just write it as... 2pq+2ph+2Qh+ pq. The last part of the question still has me confused but i think I understand the second part I just want to make sure I understand it. Please I just want to put this problem to rest. Thanks, Luis

Denis

08-22-2005, 12:30 AM

I'm still confused because wouldn't a box with an OPEN top have seven sides since there is a new side exposed. WOuld u just write it as... 2pq+2ph+2Qh+ pq. The last part of the question still has me confused but i think I understand the second part I just want to make sure I understand it. Please I just want to put this problem to rest. Thanks, Luis

No Luis; an "open top" means NO TOP whatsoever:

like a square coffee cup or something :)

Say you paint a no top box: 5 surfaces, right?

But paint a box with a top: 6 surfaces, right?

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