Answer:
Therefore the dimension of the patio is 82 feet by 41 feet.
The maximum area of the rectangular patio is 3,362 square feet.
Step-by-step explanation:
Given that, a building is constructed by using one side of the rectangular patio and facing for other 3 sides.
The length of facing is = 164 feet.
Let the length of the the rectangular patio be x which is also one side of the building.
And the breadth of the rectangular patio be y.
The length of facing
=Perimeter of the patio - common side of the building and the patio
=2(x+y)-x
=2x+2y-x
=2y+x
According to the problem,
2y+x=164
[tex]\Rightarrow x=164-2y[/tex]
The area of the rectangular patio
A= xy
Putting the value of x
A= (164-2y)y
[tex]\Rightarrow A=164y -2y^2[/tex]
Differentiating with respect to y
A'= 164-4y
Again differentiating with respect to y
A''= - 4
To find the maximum area we set A'=0
∴164-4y=0
⇒4y=164
⇒y=41.
Now [tex]A''|_{y=41}=-4<0[/tex]
Since at y=41, A''<0, Then the area of the patio will be maximum when y=41.
Then ,
x=164-(2.41)
=82 feet
Therefore the dimension of the patio is 82 feet by 41 feet.
The area of the patio = (82×41) square feet
= 3362 square feet
The maximum area of the rectangular patio is 3,362 square feet.