SOLUTION: 90. Open-top box. Thomas is going to make an open-top box by cutting equal squares from the four corners of an 11 inch by 14 inch sheet of cardboard and folding up the sides. If

Algebra ->  Numeric Fractions Calculators, Lesson and Practice -> SOLUTION: 90. Open-top box. Thomas is going to make an open-top box by cutting equal squares from the four corners of an 11 inch by 14 inch sheet of cardboard and folding up the sides. If      Log On


   

Question 170962: 90. Open-top box. Thomas is going to make an open-top box
by cutting equal squares from the four corners of an
11 inch by 14 inch sheet of cardboard and folding up the
sides. If the area of the base is to be 80 square inches, then
what size square should be cut from each corner?
Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
(11-2x)(14-2x)=80 for the base.
154-28x-22x+4x^2=80
4x^2-50x+154-80
4x^2-50x+74=0
Using the quadratic equation x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+ we get:
x=(50+-sqrt[-50^2-4*4*74])/2*4
x=(50+-sqrt[2,500-1,184)/8
x=(50+-sqrt1,316)/8
x=(50+-36.2767.)/8
x=(50-36.2767)/8
x=13.723/8
x=1.7154 in. Ans. for the square corner cut.