Answer:
The mass of the air in a room can be calculated by multiplying the volume of the room by the density of the air. The volume of the room can be calculated by multiplying its length, width, and height. So, if the room has dimensions of 1m x 2m x 3m, its volume would be 1m x 2m x 3m = 6 cubic meters. If the density of the air in the room is 1.3kg/m³, the mass of the air in the room would be 6m³ x 1.3kg/m³ = 7.8kg.