On understanding housing measures
I hope you don't have many rooms which are 4'x4'!:  That's worse than any college dorm room I ever saw.  :-)

The dimensions given for a room depend on the purpose of the measurement.  For example, for real estate advertising purposes each room is usually simplified into rectangles to the nearest foot.  Few would care that an "oval room" of 16' x 25' is exactly 314.15927 square feet, vs. a rectangular approximation of 15 x 20 which is 300 square feet.  However, measuring a room to install a carpet requires much greater precision, usually to the half inch (if not better).

For measuring a non-rectangular area, generally the best method is to break it into rectangles and add those together.

For example,



The area of this L-shaped room can be calculated in any of several ways:


Take the whole area and subtract the "hole":  22 x 24 - 12 x 14
Add the long top space and the little piece below it:  24 x 10 + 10 x 12
Add the tall space at left plus the piece at right:  10 x 22 + 10 x 14


These all evaluate to 360 square units.