For the diameter of hair the best unit is micrometre.
Identify the SI until you would use the measured the width of your classroom
You would use feet or yards to measure the width of a street.
yes
Multiply the height by the width Area = length x width or (height x width in this case)
you times the width by the legnth of the shape
It depends on what you are measuring the width of. Different units and different tools would be appropriate for a hair, a car or a galaxy.
METERS!!!The unit of measurement you would use to measure the width of your classroom is meters.
Parsecs
Centimetre.
a ruler
Millimetres
Identify the SI until you would use the measured the width of your classroom
You could use either inches or centimeters to measure the width of a sheet of paper.
15 m
a yard stick
ruler
meters