The back of Dante's property is a creek. Dante would like to enclose a rectangular area, using the creek as one side and fencing for the other three sides, to create a corral. If there is 760 feet of fencing available, what is the maximum possible area of the corral?

sandwich Feb 10, 2020

#1**+1 **

The back of Dante's property is a creek. Dante would like to enclose a rectangular area, using the creek as one side and fencing for the other three sides, to create a corral. If there is 760 feet of fencing available, what is the maximum possible area of the corral?

**Hello sandwich!**

\(A= a\cdot b\\ a+2b=760\ ft\\ 2b=760\ ft-a\\ b=380\ ft-\frac{a}{2}\)

\(A=f(a)=a\cdot (380\ ft-\frac{a}{2})\\ A=f(a)=-\frac{a^2}{2}+380\ ft\cdot a\\ A'= \frac{df(a)}{da}=-a+380\ ft=0\)

\( \color{blue}a=380\ ft\\ b=380\ ft-\frac{a}{2}=380\ ft-190\ ft\\ \color{blue}b=190\ ft\)

Dante creates a rectangular field 380ft * 190ft.

!

asinus Feb 10, 2020