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May 4th, 2013, 07:17 PM  #1 
Senior Member Joined: Apr 2013 From: Ramallah, Palestine Posts: 349 Thanks: 0  Express the Area, but this time it is open?
An open rectangular box with volume 2 m^3 has a square base. Express the surface area of the box as a function of the length of a side of the base. SO, what is the formula I need to assume for X & Y if the rectangular box is OPEN? I know before it was 2x + 2y = volume, BUT now that it is open what does that formula change to? How do I begin? Thanks. 
May 4th, 2013, 08:14 PM  #2  
Math Team Joined: Oct 2011 From: Ottawa Ontario, Canada Posts: 8,755 Thanks: 604  Re: Express the Area, but this time it is open? Quote:
We're not here to do your homework. Can you give us the volume of a box with square base 5 by 5 and a height of 4 ?  
May 20th, 2013, 02:49 PM  #3 
Senior Member Joined: Apr 2013 From: Ramallah, Palestine Posts: 349 Thanks: 0  Re: Express the Area, but this time it is open?
Denis, I'm a moron. I wasn't differentiating the difference between volume and perimeter. Lol my apologies. I know that L*W*H = V So, what am I looking at here? It's only giving me 2m^3 and it is telling me to express the SURFACE AREA of the box as a function of the length of a side of the base. Sorry the book doesn't give any examples on this problem in this section, it is a harder problem. One that you get help with, I was under the impression I could come here to ask for help Denis. I wasn't asking you to do the problem. I was asking you "Where do I start?" Or, what formula should I know to use to solve this problem. Anyways, I am still lost. So can anyone give me some insight on what to do or where to start? Bashing me telling me you aren't going to do my homework and then asking me how to do a problem that is allot easier then the problem I'm asking help for is not really helping me, but thanks anyway Denis. Again, here is the problem : An open rectangular box with volume 2 m^3 has a square base. Express the surface area of the box as a function of the length of a side of the base. 
May 20th, 2013, 06:53 PM  #4  
Math Team Joined: Oct 2011 From: Ottawa Ontario, Canada Posts: 8,755 Thanks: 604  Re: Express the Area, but this time it is open? Quote:
x = sides of base; h = height So, since volume = 2, then : x * x * h = 2 h = 2/x^2 Surface area is base which is x^2, and 4 "walls", each xh; so: Area= x^2 + 4xh ; substitute h = 2/x^2 : Area = x^2 + 4x(2/x^2) = x^2 + 8/x which can also be written as (x^3 + / x  

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