SOLUTION: A rectangular piece of cardboard 11 inches by 14 inches is made into a box by cutting identical squares from each corner and folding up the sides. If the bottom of the box turns o

Algebra ->  Customizable Word Problem Solvers  -> Geometry -> SOLUTION: A rectangular piece of cardboard 11 inches by 14 inches is made into a box by cutting identical squares from each corner and folding up the sides. If the bottom of the box turns o      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


   



Question 1054231: A rectangular piece of cardboard 11 inches by 14 inches is made into a box by cutting identical squares from each corner and folding up the sides. If the bottom of the box turns out to have an area of 80 in^2, what size squares were cut from the corners?
The equation I am coming up with does not give me an answer that would fit.

Found 2 solutions by Fombitz, jorel555:
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
So you fold up a square of size, X, from each edge.
Let's call the left over part A on the width and B on the length so that,
X%2BA%2BX=11
X%2BB%2BX=14
.
.
2X%2BA=11
2X%2BB=14
and the area of the bottom,
AB=80
So from the length and width,
A=11-2X
B=14-2X
Substituting,
%2811-2X%29%2814-2X%29=80
4X%5E2-50X%2B154=80
4X%5E2-50X%2B74=0
2X%5E2-25X%2B37=0
Complete the square,
2%28X%5E2-%2825%2F2%29X%29%2B37=0
2%28X%5E2-%2825%2F2%29X%2B%2825%2F4%29%5E2%29%2B37=2%2825%2F4%29%5E2
%28X-%2825%2F4%29%29%5E2=625%2F16-296%2F16
%28X-%2825%2F4%29%29%5E2=329%2F16
X-25%2F4=0+%2B-sqrt%28329%29%2F4
X=25%2F4+%2B-+sqrt%28329%29%2F4
Although there are two answers, we are limited by,
A%3E0
B%3E0
which leads to the solution,
X=25%2F4-sqrt%28329%29%2F4

Answer by jorel555(1290) About Me  (Show Source):
You can put this solution on YOUR website!
Let n be the length of the sides of the squares cut from the box. Then:
(11-2n)(14-2n)=80
154-50n+4nē=80
4nē-50n+74=0
2nē-25n+37=0
Using the quadratic formula, we get n=10.7845892868 or 1.7154107132. Throwing out the higher result, we get the size of the squares to be 1.7154107132 in. x 1.7154107132 in. ☺☺☺☺