xaudbo fu'ivla

x1 is \sqrtA = \sqrt2×5 [decimal: 1\times10+(1/2)] of x2 in dimension/aspect x3 (default is units).

This works as all other Metric prefixes do. In decimal, 10(1/2)=\sqrt(10)=3.16227766\dots (also expressed/represented in decimal). In different bases, this value may change; for example, in hexadecimal, it might be exactly four (4); however, this is an outstanding as-of-yet unsolidified area in the Lojban grammar/semantics (do "ki'o" and Metric prefixes change according to the base?). This number is nice, as it is close to both 3 and and the circle constant pi (\pi) in decimal usage; these three values arise fairly frequently and a great trick in decimal Fermi estimation is to use their approximate identity in order to simplify expressions. Now, when the quantity is dimensionful (has units), if the mantissa approximates this value, then one can instead express the mantissa as approximately 1 and the unit as being augmented by this prefix. This word is also good for short-hand/quick expressions. This word has no English equivalent and is not part of the official set of SI prefixes, but it does generalize them. "xaudbo" = "kamre li dau te'a 1/n, "n/" => n/1, or "/" alone => golden ratio.">fi'u re" in decimal (if it generalizes for other bases, change "dau" into the base; in other words, "dau" generally becomes "pano" in such case, where the base is given by context). While this suggestion is not perfectly compatible with SI (which allows only one prefix at a time), the negative-power version of this ("kamre li dau te'a ni'u fi'u re", where "dau" has the aforementioned caveats; 1\times10-(1/2)) can just be expressed as a lujvo/rafsi/tanru containing both "decti" and this word (as veljvo/selrafsi/seljavytertau), because A(-1/2)=\sqrt(1/A)=A(+1/2)/A, and A (ten in at least decimal) is the base. A "xaudbydectre" is a single unit which (in decimal) happens to approximate an imperial/U.S. customary foot (unit). See also: "namcrgogolo"/"kamrngogolo", "kacmre", "zilkacmre", "kancu", "merli", "radno", "stero", "molro", "gradu", "centi", "decti", "dekto", "femti", "gigdo", "gocti", "gotro", "kilto", "megdo", "mikri", "milti", "nanvi", "petso", "picti", "terto", "xatsi", "xecto", "xexso", "zepti", "zetro", "kamre", "nulpa".