I'd use inches, but centimeters could also work.
A millimetre.
mm
millimetres or even micrometres.
Metres, to measure its length or width, square metres to measure its area.
I would use meters.
Depending on your countries standard unit of measurement but either feet or meters would be the answer.
Centimetre.
Parsecs
METERS!!!The unit of measurement you would use to measure the width of your classroom is meters.
ruler
You would use either inches or centimeters.
meters
mm
Centimeter
appropriate unit to measure the width of a textbook = ce ntimeters
millimetres or even micrometres.
Millimetre.
Identify the SI until you would use the measured the width of your classroom