One hundred sixty eight square feet of carpet has been ordered for a 12 foot wide room. how long should the room be?

      
                               Area = (length) x (width)

                                                 168 square-feet  =  (length) x (12 ft)

Divide each side by  12-ft :    (168 sq-ft) / (12-ft) = length

                                                                   14-ft  =  length .

Since the carpet has already been ordered and the order
can't be changed, if the room is not  14-ft  long, then the
room must be either cut down or added onto.