Answer:
The maximum area is 
Step-by-step explanation:
Let
x----> the length of rectangle
y---> the width of rectangle
we know that
The perimeter of rectangle is equal to

we have

so


------> equation A
Remember that
The area of rectangle is equal to
-----> equation B
substitute equation A in equation B

This is a vertical parabola open downward
The vertex is a maximum
The y-coordinate of the vertex of the graph is the maximum area of the garden and the x-coordinate is the length for the maximum area
using a graphing tool
The vertex is the point 
see the attached figure
Find the value of y
-----> 
The dimensions of the rectangular garden is
by 
For a maximum area the garden is a square
The maximum area is 
It took Dina 20 minets to wash her dog hope this helped
<span>l ≤ 12
2l + 2w < 30
the second and fourth option are saying she can make the length longer than twelve and the third option forgets to double the length and width so it is accurate. The first option is the right answer.</span>
0.0000079 is your answer, I believe.