But this has been exacerbated by human activities which have led to: 1) an increase in greenhouse gas emissions that causes heat to remain trapped within the troposphere, and 2) a decrease in ozone in the stratosphere, causing less sunlight to be absorbed by the ozone layer, resulting in a cooling of the stratosphere.
When measuring for floor tile the rule is: Length x Width + Waste = Amount Needed. Waste Factor will vary based upon tile size, layout, configuration of room, patterns, etc. Typical waste factor is about 10%. Add 15% for tile being installed diagonally or for a room with lots of jogs and corners.
For real estate advertisings and listings, most agents determine square footage by measuring the exterior dimensions of the house. To calculate square footage in this way, you would measure corner-to-corner or end-to-end. Then take the sum of the exterior length of the house and multiply by the sum of the exterior width. Real estate agents often measure straight corner-to-corner, then deduct non-heated spaces, and add heated spaces whose footprints exceed the end-to-end measurement.