So, to find perimeter, you add all sides.
So, if the length is 42 yards and the width is 27, then we need to add 42 + 42 + 27 + 27.
42 + 42 = 84.
27 + 27 = 54
84 + 54 = 138
Daniel will need 138 yards of metal border.
Glad I could help, and good luck!
AnonymousGiantsFan