Re^2: Constants you cannot help but remember

[hawtin]

In metric the size of the earth is easier since the French originally defined the metre to be 1/10000000th of the distance from the North Pole to the Equator through Paris. (the definition has changed but the value is still close enough)

That's a really easy constant to remember. I have needed it often even if those living in the US would rather use feet (or Survey Feet, or Clarke's feet, or whatever) (for which I can always remember the conversion factor 0.3048 by the way)