you first have to find the area of the room, so the total square feet on the inside, then take that number and multiply by the amount per square foot m 13x15=195 (total sq ft of the room) 195 x 1.15 = 224.25
Explanation: If a building is 380 feet tall and the elevator has to descend 420 feet to get to the underground parking garage. So 420 - 380 to remove the height of the building from the equation. This would give us 40 feet underground left until the elevator reaches its desired destination.
