What is Formula to convert SY to LF?

If the width "W" of your area "A" is, say one yard, that is, 3 feet, then you divide the Area "A" by width "W" to equal length, "L"

A = W x L or, A/W = L but since A is in square yards, you need to multiply by 3 (3 ft in a yd) to get L in linear feet.

Then the formula becomes, 3(A/W) = L in linear feet