Less than One: Unit Measurements Singular or Plural?

Less than One: Unit Measurements Singular or Plural?   (01/30/2012, 4:41 PM)

When we indicate an amount less than 1, such as 0.1 acre, meter, etc., is the unit singular or plural? For example, our non-scientific staff at work indicate "The project area is 0.1 acres" but should "acres" be singular?