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September 30, 2014

September 30, 2014

Posted by **Chelsea** on Tuesday, January 31, 2012 at 7:22pm.

- Math -
**Reiny**, Tuesday, January 31, 2012 at 8:15pmlet the width of the field be x ft

let the length be y ft

so y + 2x = 80

or y = -2x + 80

area = xy

= x(-2x+80)

= -2x^2 + 80x

do you know Calculus?

if so ...

d(area)/dx = -4x + 80 = 0 for a max area

4x = 80

x = 20

width is 20 ft, length is 40 ft.

largest area = 20(40) = 800 ft^2

If you don't know Calculus, complete the square

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