Am 07.03.2018 um 03:48 schrieb Alain:

> The formula use meter, a meter = about 39 inches, or 3 feet and 3 inches
> (3.25 feet in 1 m).
> There are 10.5625 square feet in a square meter.

Sorry to be blunt, but with that many decimals, that number is a lie, as
it implies a precision it doesn't have.

As a rule of thumb, whenever you're doing mathematical computations with
approximate values, it is good practice to round the end result to the
lowest number of significant digits of any of the "input" values.

Also, since the UK imperial and US customary units are defined in terms
of the metric system (yes, you UK folks have been using the metric
system ever since 1930, and you US folks even since 1893(*); it's just
been hidden from you :P), that's what I'd recommend to start with:

(A) from the 1930 BSI (UK) / 1933 ASA (US) definition:

1 inch = 25.4 mm = 0.0254 m
1 foot = 12 inch = 0.3048 m

(B) from the 1959 International Yard and Pound Agreement:

1 yard = 0.9144 m
1 foot = 1/3 yard = 0.3048 m

Either way:

1 square foot = 0.09290303 m^2
1/0.09290303 square feet = 1 m^2

These numbers are exact, by virtue of definition of the UK imperial and
US customary units. Alternatively, here's a high-precision approximation:

10,7639104167097223083335055559 square feet = 1 m^2


(* The 1893 Mendenhall Order (US) definition had 1 yard = 3600/3937 m,
which gives slightly different results, and has remained the basis for
the survey foot.)

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