Answer:
4050 sq. feet.
Step-by-step explanation:
Fencing is done on three sides of the rectangular area.
Given that there are 180 feet of fence available.
Then 2L + W = 180 ........(1), where L = length and W = width, of the rectangular plot.
Now, the area of the plot is given by A = LW
Now, from equation (1), we ger A = L (180 - 2L) ..... (2)
Then differentiating with respect to L in the both sides we get,
[tex]\frac{dA}{dL} = 180 - 4L =0[/tex] {Since condition for Area to be maximum is [tex]\frac{dA}{dL}=0[/tex]}
⇒ L = 45 feet.
Now, from equation (2), we have [tex]A_{max} =L(180-2L) = 45(180 - 90) =4050[/tex] square feet.