Answer:
The maximum rectangular area will have the length 400 meters and width 200 meters with one side of the length against an existing building.
Step-by-step explanation:
From the given information;
The perimeter of a rectangle = 2 (L+B)
here;
L = the length of the side of the fence
B = the width of the fence
So; The perimeter of a rectangle = 2L+2B
we are also being told that;
One side of the area will be against an existing building
i.e
The perimeter of a rectangle is now = L + 2B = 800 meters
L = 800 - 2B
Similarly; Area of a rectangle = L × B
Area of a rectangle = ( 800 - 2B) × B
Area of a rectangle = 800B - 2B²
assuming A(B) to represent the Area;
Then the maximum area A'(B) = 0 ;
Thus,
A'(B) = 800 - 4B = 0
-4B = - 800
4B = 800
B = 200
Therefore; the maximum area have a width = 200 meters and a length 800 - 2(200) = 800 - 400 = 400 meters
