That depends what you want to measure about the room: for example its temperature, its color, etc.
Feet or meters
Degrees Celsius.
Metres most likely, or feet.
cm
Centimetres.
Feet or meters
I would use meters.
You would use the metric unit "meters" to measure the length of a room.
Class room can be measure in Meters easily :)
Degrees Celsius.
Square feet is a common unit used to measure the area of a room in a house. It provides a good measure of the total floor space available within the room.
Metres most likely, or feet.
division
You would use the unit of measure called "kilograms" to measure the mass of an elephant.
cubic meters
Fahrenheit or Centigrade (Celsius)
The Unit Used To Measure A Train Can Be Kilometer.