Airerectangle:Area for width
Primtrerectang:Perimeter for length
airlength:Area for length
airperim:Area for perimeter
areadiff:Area and difference *
areadiff2:Area and difference II *
areaprop:Area and proportion *
areaprop2:Area and proportion II *
peridiff:Perimeter and difference
perimwidth:Perimeter for width
widlen:Length - width *
