Why in the world are centimetres ever taught in school? I find them to be the most pointless unit of measurement ever. They are either too big for one thing or too small for another.
Why can't people either use millimetres, meters or inches for god sake. I've been trying to send a parcel and the online form has asked me for the measurements in cm. I entered them in as 64.3cm, 45.5cm and 40cm as that was what they were. It then says that my parcel has a combined total girth of 222cm which is over their 220cm limit.
NO IT F***ING ISN'T!!! last time I checked. 64.3 x 2 + 45.5 x 2 = 219.6cm. I realise this is only just under the limit but it is under it. To get 222cm I assume they have rounded 64.3cm up to 65cm which is a. wrong and b. if you are rounding 45.5cm up to 46 then you should be letting me off for that 0.6cm.
My problem is that if I say its 64cm and someone checks and finds its over (they will if they use a tape measure in mm) and round it up like the website does then I am going to get hit with a £50 charge and I am not prepared to take the risk.
Millimetres are better than centimetres for a lot of other reasons as well. They give some quite nice conversions in engineering, 1 N/mm^2 is equivalent to 1 MPa which is used a lot for material properties so you don't have to keep using factors to correct equations and when working with them you end up with more accurate parts. I work in an industry that makes castings. Even we can make castings that are within +/- 2mm. The patterns we use are made to within +/-0.1mm so 1cm is frigging huge in comparison.
Rant over. Off to find a different courier.