Answer:
Length = 36 ft
Explanation:
We are told the width of the field is 12 ft shorter than the length.
This means that;
Width = Length - 12
Let's denote width by W and length by L.
Thus;
W = L - 12
Now,we are told the perimeter is 120 ft.
Formula for perimeter of rectangle is;
2(Length + Width)
Thus;
2(L + W) = 120
Putting in L - 12 for W gives;
2(L + L - 12) = 120
Divide both sides by 2 to give;
L + L - 12 = 120/2
2L - 12 = 60
2L = 60 + 12
2L = 72
L = 72/2
L = 36 ft