math
posted by Jane on .
The length of an opentop box is 4 cm longer than its width. The box was made from a 480cm^2 rectangular sheet of material with 6cm by 6cm squares cut from each corner. The height of the box is 6cm. Find the dimensions of the box.
Please show me in detail how to set this up and solve.

area of sides = 2 L *6 + 2 W*6
= 12 L + 12 W
area of bottom = L W
total area = L W + 12 L + 12 W = 4804*36
so
L W + 12 L + 12 W = 336
but L = W + 4
(W+4)W + 12(W+4) + 12 W  336 = 0
W^2 + 28 W 288 = 0
(W 16)(W+18) = 0
W = 16
L = 16+4 = 20 
l=4+w
w=l4
h=6
v=480
v=lwh
480=12 x 8 x 6 
UR wELCOME