Mr. Smith would like to enclose a rectangular field that has an area of 1000 square feet. What is the minimum amount of fencing he will need if he only needs to use it on 3 sides since he can use the side of the barn for the fourth side.

Answer 1

P=2W+L
LW=1000

P=2W+1000/W

dP/dw=2-1000/W^2=0
solve for W first, then L, then Perimeter (length of fencing)

Answer 2

L=22.360
W=44.722