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.
best u nit to measure the length of bedroom = meter
Class room can be measure in Meters easily :)
Degrees Celsius.
Square feet is a good unit to measure the area of a room in a house.
Metres most likely, or feet.
You would use the unit of measure called "kilograms" to measure the mass of an elephant.
division
cubic meters
Fahrenheit or Centigrade (Celsius)
Perimeter is a length or a distance, just like depth, height, and circumference are. Any unit of length can be used to describe a perimeter. Some good ones are ... - nanometer - inch - kilometer - parsec - furlong - yard - league - mile - light-year.