Can you explain how to do this please (Geometry)?

Question

A garden that is 5ft by 6ft has a walkway 2ft wide around it. Find the amount of fencing needed to surround the walkway.

Answer 1

width with walkway = 5+4 =9
length with walkkway = 6+4 = 10
So perimeter = 2(9+10)= 38 feet

Answer 2

draw a square and label it 5 ft by 6 ft. Draw another square around that and note that each side is 2 ft away from the inner square. Some quick addition tells you that the bigger square (the outer edge of the walkway) is 9 ft by 10 ft. To get the perimeter of the square add up the lengths of the four edges to get 38 ft.

Answer 3

take the garden dimensions and add 4ft onto each one
5ft x 6ft
9ft x 10ft

then just work out the perimetre (if thats how you spell it) and that gives you the length of fencing needed