
Mark M. answered 04/19/16
Tutor
5.0
(278)
Mathematics Teacher - NCLB Highly Qualified
Draw a label a diagram!
The pen has a "top" and a "bottom." Represent each by t.
The pen has four "sides." Represent each by s
2t + 4s = 400
The area of each pen is st
A = st
2t + 4s = 400
2t = 400 - 4s
t = 200 - 2s
A = s(200 - 2s)
A = -4s2 + 200s
Maximum occurs at -b/2a, or -200/-8, or 25
Each side is 25 feet. The top and bottom are each 150 feet.
Area equals 25 x 150.