Arrange the areas , , and in descending order.
Converting to the same square unit can help us arrange the areas.
There are square millimetres in 1 square decimetre, so we multiply the number of square decimetres by to convert the first area to square millimetres.
There are 100 square millimetres in 1 square centimetre, so we multiply the number of square centimetres by 100 to convert the third area to square millimetres.
> > , so the areas arranged in descending order are , , .