Kilometres are the appropriate unit.
The metric unit of the meter would be the appropriate measure of the area of classroom. Calculating area involves multiplying the length (in meters) of the classroom's length and width. Area of the classroom would be in square (^2) meters.
We can measure how long things are , how tall,or how far apaart they are .Those are examples of length meaasurements. The basic unit of length is meters.
Unit of length for the width of soccer field is meters.
The international (SI) unit for mass is the kilogram.
I say miles that's how the car does it; and kilometres in the SI system.
yards
A centimetre.
Hs
feet
miles
By unit of length and distance and conversion ,we can say that the most appropriate unit to measure the length of a finger is cm.
Meters
feet
millometers
millimeter
Meters