we know that
[perimeter of rectangle]=2*(length+width)
Let
x-----------> length
y-----------> width
so
P=2*(x+y)-----------> 244=2*(x+y)-----> x+y=122-------> y=122-x
Area=x*y-------> x*(122-x)----> 122x-x²
find the derivative function and equals to zero
122-2x=0-----> 122=2x----------> x=61 m
y=122-x------> y=122-61---------> y=61 m
the maximum area is given by a square
the answer is
is a square of side 61 m