Question

A landowner wants to fence in a rectangular area of 60000 square metres and divide it into three parts with two parallel fences both parallel to one side of the rectangle. Each part will have a different grazing crop for the herds. What is the shortest total length of fence that he can use?

Answer 1

as usual, divide the fencing equally among lengths and widths. So, I'll go ahead and predict that the solution will be

7500 x 15000

Answer 2

oops. wrong problem.

y = 60000/x

p = 2x+4y = 2x + 4(60000/x)
dp/dx=0 when x=200√3 and y=100√3

p = 800√3

But, as usual, the length is equally divided among lengths and widths.