Convert from palm [Britain, Roman minor] to arms-length

Unit Definition (palm [Britain, Roman minor])
A palm, when used as a unit of length, is usually four digits or three inches, i.e. 7.62 cm (for the international inch). The width of an adult human male palm is indeed about 10 centimetres.In English this unit has mostly fallen out of use, as do others based on the human arm: digit (¼ palm), finger (7/24 palm), hand (4/3 palms), shaftment (2 palms), span (3 palms), cubit (6 palms) and ell (15 palms).

Unit Definition (arms-length)
An Arms length is standardized as a unit of distance equal to approximately 70 centimeters, or 28 inches. An arms length is the same as the modern Italian Braccio and very similar to the Turkish Pik.