# area and volume

• Sep 4th 2012, 03:50 PM
allison
area and volume
(Hi) can anyone help me solve this problem, please?
A piece of cardboard measures 40 cm by 40 cm. An open-topped box is to be constructed by removing a square with side length of 8 cm from each corner and folding up the edges.Find the surface area of the box. Find the volume of the box.
• Sep 4th 2012, 04:13 PM
pickslides
Re: area and volume
The open topped box will have dimensions of length = 40- 2(8) = 24 cm, width = 40- 2(8) = 24 cm & height 8 cm

Now what are the formulas for surface area (as it is open topped, do you need to do indside and out?) and volume?
• Sep 4th 2012, 04:17 PM
allison
Re: area and volume
Thank you very much pickslides for the reply. yes, i need to find out the surface area and volume of the box? can you help me please?[/SIZE]
• Sep 4th 2012, 04:29 PM
pickslides
Re: area and volume
Surface area of a closed box is $\displaystyle 2(LW+LH+WH)$ but yours is an open box so subtract the top i.e. $\displaystyle LW$ from the result.

If you are counting both the inside and outside multiply this result by 2.

Volume of a box is $\displaystyle L\times W\times H$
• Sep 4th 2012, 04:42 PM
allison
Re: area and volume
Quote:

Originally Posted by pickslides
Surface area of a closed box is $\displaystyle 2(LW+LH+WH)$ but yours is an open box so subtract the top i.e. $\displaystyle LW$ from the result.

If you are counting both the inside and outside multiply this result by 2.

Volume of a box is $\displaystyle L\times W\times H$

Hey pickslides you are a GENIOUS!!
so, "subtract the top i.e. LW from the result" as you have mentioned above. do i have to do this then 2(LW-LH-WH)

Also, i got the volume - > volume= (l*w*h)=24*24*8=4608

• Sep 4th 2012, 04:46 PM
pickslides
Re: area and volume
Do $\displaystyle 2(LW+LH+WH) - LW$ if you are counting the inside, multiply the result by 2 i.e. $\displaystyle 2\times [2(LW+LH+WH) - LW]$
• Sep 4th 2012, 04:57 PM
allison
Re: area and volume
Quote:

Originally Posted by pickslides
Do $\displaystyle 2(LW+LH+WH) - LW$ if you are counting the inside, multiply the result by 2 i.e. $\displaystyle 2\times [2(LW+LH+WH) - LW]$

if i am not wrong i got the answer as 1520 by calculating 2*[2(lw+lh+wh)-lw]
and volume as 4608. Hope i am right..

thank you so much for your time. i greatly appreciate your help.