SOLUTION: I have the problem a rectangular piece of paper is three times as long as it is wide. From each of its corners the square of 3 cm is cut out. The flaps at each corner are then tu

Algebra ->  Rectangles -> SOLUTION: I have the problem a rectangular piece of paper is three times as long as it is wide. From each of its corners the square of 3 cm is cut out. The flaps at each corner are then tu      Log On


   



Question 878394: I have the problem
a rectangular piece of paper is three times as long as it is wide. From each of its corners the square of 3 cm is cut out. The flaps at each corner are then turned up to form an open box. The volume of the box is 189 cm³. Find the original dimensions of the piece of the paper.
A) 2cm x 21 cm
B) 4.6 cm x 13.8 cm
C) 9 cm x 27 cm
D) 25.8 cm x 77.4 cm
I'm not sure I am correct so far but this is what u have done
L x w x h = V
(3x)(x)(3) =189 cm³
9x^2 = 89 cm³
I don't know what to do next or if that's right so far. Please help, thanks so much!

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
The sheet is x by 3x
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After it's cut, it's x-6 by 3x-6
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Vol = 3*(x-6)*(3x-6) = 189
(x-6)*(x-2) = 21 (make it easier)
x%5E2+-+8x+%2B+12+=+21
x%5E2+-+8x+-+9+=+0
x = 9 (Ignore the -1 solution)
--> 9 by 27