<PRE><B>Question 1037299</B>
x=sides
y=front and back
xy=300, area
Cost=7(2x+y)+28y=14x+35y
y=300/x
cost is 14x+10500/x
Take the derivative and set it equal to zero.
14-10500/x^2=0
14=(10500/x^2)
14x^2=10500
x^2=750
x=27.38 feet.
y, the amount of redwood fencing, is 10.96 feet.  Total cost is 65.72@$7=$460.04 plus 10.96*28=306.88=$766.92
check with 25 and 12 for area of 300
62 feet of chain ($434)
12 feet of redwood (336), total is $770.
30 and 10--90*$7=$630 and 10*$28=$280, for total of $910.
{{{graph(300,200,-10,40,-100,2000,14x+(10500/x))}}}</PRE>