Maybe the 'D' is being held in reserve. The prefix deca isn't used much and, like centi, deci and hecto, it doesn't fit the pattern of all the other prefixes which are in powers of 1000.
These prefixes representing multiples within the rang 0.01 - 100 are not really needed although there is a problem with area and volume because of the jump in magnitude. For example the ratio of cubic metre to the cubic kilometre (10^9). As for 'k' for kilo maybe that is because of the 'K' for kelvin (context would resolve ambiguity but it wouldn't be very elegent). With hindsight it may have been better to use 'k' for kelvin and 'K' for kilo but I guess it's too well established now and would be difficult to make the change without causing confusion. ----- Original Message ----- From: "Ametrica" <ametr...@cox.net> Sent: Wednesday, 16 June, 2010 4:18:19 AM Subject: [USMA:47810] RE: The Oil Leak (Estimate) Increases Again It would be easier to understand if the symbol for deka was "D". Since we have "m" for milli and "M" for mega, there would be no conflict with deci, which is "d". It would also reduce the symbol from two letters to one letter. What do you think? I also think hecto should be "H" and kilo "K". This way all multiples have their prefixes as capital letters and all sub-multiples as miniscule letters. Most are this way except for deka, hecto and kilo. I've seen road signs in some countries that had kilometre as "Km". some people may think that is the rule.
