Since you are to find out the length of material that will be used for fencing when its width is 24m and its length is 28m then you are to find the perimeter.
The formula of perimeter for a rectangle is
P = 2l + 2w
Substituting you'll have:
P = 2(28m) + 2 (24m)
P = 56m+48m
P = 104m
