Answer:
Half of the perimeter is 300 feet.
If 100 feet are in the width, then 200 feet are in the length
Explanation:
Perimeter is the sum of the lengths and the widths of the rectangle.
So P= l + l + w + w
perimeter is 600 and the width is 100.
so substituting in
600= 100 + 100 + l + l
600 = 200 + 2 l
solve for l
l = 200
hope this helps