1. ## help with function!

Q:
An open box is made from a cardboard square that is 40cm on a side by cutting a square out from each corner and then turning up the remaining sides. express the Area A of the base of the box as a function of the length x of the side of the cut out sqaure.

....can someone pls explain to me this problem!!!

2. I did it this way with the following rather spiffing diagram:

3. Originally Posted by geeko
Q:
An open box is made from a cardboard square that is 40cm on a side by cutting a square out from each corner and then turning up the remaining sides. express the Area A of the base of the box as a function of the length x of the side of the cut out sqaure.

....can someone pls explain to me this problem!!!
Is this figure accurate (not drawn to scale)? If so, then the area of the base has to be:

$A=(40-2x)^2$

since you cut off $2x$ lengths from each side. The red area would be the bottom of the box. Each side would be 40-2x.