math
posted by Daphne on .
I need to enclose a section that is 250 square ft with a fence that cost $1.50 per yard, what dimension would i use to minimize the cost?

You don't specify what shape your enclosure is to have.
The shape which has the most area for the least perimeter of course is the circle.
so πr^2 = 250
r = 8.9206
and the circumference
= 2πr = 2π(8.9206)
= 56.05 ft
= 18.68 ft
So you will have to buy 19 yards for a cost of $28.50
If you want a 4sided shape, it will be a square
side^2 = 250
side = 15.811
perimeter = 4s = 63.25 feet
= 21.08 yards.
in this case you will need 22 yards, since 21 yds are not enough
for a cost of $33