Answer:
216 square feet
Explanation:
Area of rectangular field = 3456 sq ft
Width = 48
So length = 3456/48 = 72
The length and width of the fenced-in area are 1/4th of that of the field
So for fenced-in area
length = 72/4 = 18
width = 48/4 = 12
Area of fenced-in portion = length x width = 18 x 12 = 216 square feet
Additional Note
Since we know the area of the field and the fact that the fenced-in area has a width and length 1/4th of the field, it can be computed by knowing the area alone
If both length and width are 1/4th, then area is reduced to 1/16th of original area
3456/16 = 216
No need to know the field width or length to answer this question