
Bradford T. answered 07/12/21
Retired Engineer / Upper level math instructor
By largest rectangle means rectangle with the largest area given the total fence length.
Let L = the length of the rectangle and W = the width of the rectangle. The width will be divided into 3 sections which means two extra divider fences.
Perimeter plus inner fencing, P for a rectangle is 4L + 2W= 97.
L = (97-2W)/4 = 24.25 - W/2
The total area, A = LW = 24.25W-W2/2. To maximize the area, take the derivative of the area, set that to zero and solve for W.
A(W) = 24.25W-W2/2
A'(W)= 24.25-W
W= 24.25 m
L = 24.25-24.25/2 = 12.125 m