Draw a picture of the yard, rectangle. On the two long sides, write 28 yards and on the two shorter ones, just write a question mark.
To figure out perimeter, you need to add up each side.
P = Perimeter
L = Length
W = Width
P = L(2) + W(2)
If the length is 28, double it. = 56
Now subtract that from the perimeter - 88-56=32
32 is what you have left, so now split that, and replace the question marks.
All-in-all each width is 16 yards, while each length is 28, making the whole rectangle have a perimeter of 88 yards.