How many km is in 42 mm?

Answer 1

The process. Km is a 'kilometre' - a thousand metres (m), thus a hundred thousand centimetres (cm), thus a thousand thousand (a million) millimetres (mm). So there are a Million Millimetres in a Kilometre. So, a mm is one millionth of a kilometre and so 42 mm is 42 millionths of a kilometre. A millionth as a decimal of 1 = 0.000001 (Six noughts and then the 1; the reverse view of a 1 and six noughts / zeroes which would equate to a (positive) Million. So 42 millionths of a kilometre would be 42 times (x) the millionth figure) and thus 0.000042 (parts of a) km. Hope this helps!