Thursday

March 5, 2015

March 5, 2015

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

**Answer this Question**

**Related Questions**

intermediate algebra - A farmer with 3000 feet of fencing wants to enclose a ...

Calculus - 600 feet of fencing to enclose a rectangular plot If I don't fence ...

Math - Please help!!! Scott bought 54m of fencing to enclose a rectangular plot ...

calculus help - Farmer Brown wants to fence in a rectangular plot in a large ...

Math - Show all work You have 92 feet of fencing to enclose a rectangular plot ...

math - A farmer with 2000 meters of fencing wants to enclose a rectangular plot ...

Math (Quadratic Equations) - A field is bound on one side by a river. A farmer ...

Math - A farmer with 8000 meters of fencing wants to enclose a rectangular plot ...

Algebra - You have 600 feet of fencing to enclose a rectangular plot that ...

College Algebra - You have 800 feet of fencing to enclose a rectangular plot ...