How do you measure square feet?

Answer 1

Square feet is an imperial measure of area. To measure a floor, or wall to find the area we do the following

As these are rectangular we need both the length and the width (floor) or length and height (wall).

As most floors and walls are rarely exact numbers of feet we tend to convert the measurements to inches, to make calculations easier

If the length of a floor is 12 foot 5 inches and the width is 8 foot 7 inches we convert 12 foot 5 inches to 149 inches and 8 foot 7 inches to 103 inches.

Then we multiply these two measurements to get square inches - 149 times 103 = 15,347 square inches.

As there are 144 square inches in a square foot (12 inches by 12 inches = 144 square inches) we now divide 15,347 by 144 and get 106.57 square feet.

The same process is carried out for any regular rectangular area - multiple the length of one dimension by the length of the other.

We could have converted the feet and inches above to feet with decimal representation of the inches. 12 foot 5 inches = 12.41667 feet; 8 foot 7 inches = 8.583; and multiplying those would give the same answer - 12.41667 times 8.583 = 106.57 sq feet.

For non-rectangular areas we need to use either triangular or circular geometry - but instances of these are too specific in details to be answered in a general question like this.