Arectangular plot of land that contains 1500 square meters will be fenced and divided into two equal portions by an additional fence parallel to two sides. find the dimensions of the land that require the least amount of fencing.

Let the length be x and the width be w

The perimeter will be:
2x+3w=1500

thus
3w=(1500-2x)
w=(1500-2x)/3
w=500-2/3x

The area will be:
A=x*w
A=x(500-2/3x)
A=500x-(2/3)x²

The above is a quadratic equation; thus finding the axis of symmetry we will evaluate for the value of x that will give us maximum area.

Axis of symmetry:
x=-b/(2a)
from our equation:
a=(-2/3) and b=500
thus
x=-500/[2(-2/3)]
x=375
the length will be 375 m

The width will be 250 m