The british thermal unit(btu) is a unit of energy used globally in air conditioning industries. the number of btus needed to cool a room depends on the area of the room. to find the number of btus recommended for any size room room, use the formula b=377lw, where b is the number of btus, l is the length of the room, and w is the width of the room. the room you want to cool uses the recommended number of 12,252.5 btus and is 5 meters wide. find the area of the room