The measurements given 30 feet by 15 feet should tell you that the shape of the area is a rectangle.
In this case, find the perimeter to get the total length of rope she need.
Perimeter of a rectangle,P = 2(l+w) where l is length =30 feet and w is width , 15 feet and P is perimeter.
P= 2(l+w)
P =2(30+15)
P=2(45)
P=90 feet.
The rope she will need is 90 feet. Answer.