You must know at least one side to convert into square ft

Area = Length x width

linear ft is a length.

So to go from square ft to linear ft you must have one side example

200 square ft with one side being 20 ft

200 / 20 ft = 10 ft

You now know both sides. But the total linear for the whole perimeter of 4 walls is

10 + 10 + 20 +20 = 60 linear ft

Area = Length x width

linear ft is a length.

So to go from square ft to linear ft you must have one side example

200 square ft with one side being 20 ft

200 / 20 ft = 10 ft

You now know both sides. But the total linear for the whole perimeter of 4 walls is

10 + 10 + 20 +20 = 60 linear ft