1 ft = 100÷3=33.33 cm. 2 feet =2X33.33 cm =66.66 cm. 2' 2 is the daily name for the waist of trousers, that is, 2' 2 ". But this is not a standard dimension. In order to unify the standard and make it easy to understand, metric dimensions such as centimeters or millimeters are generally used now. So 2 feet 2 is 2.2X33.33 cm =73.326 cm.
Introduction of ruler
Chi (pronounced chǐ, chě) is a standard first-class word in modern Chinese. The earliest glyph of this word is Oracle Bone Inscriptions. The original meaning is a unit of length, and later it is extended to a tool for measuring length, that is, a ruler; It is also extended to something shaped like a ruler, such as a weight.
Scholars such as Shuowen and Duan Yucai's Notes on Shuowen Jiezi think that ruler is a knowing word, from "corpse" to "b", and "corpse" is like the image of a person lying down, and "b" is a sign, and all the dimensions of measuring inch, zhi, ruler, cutting, searching and keeping are based on human body.
Others think that "ruler" refers to things. In Oracle Bone Inscriptions, the long bend is vertical to indicate the whole arm, and the middle point is an indicator, indicating the bend of the arm, that is, the elbow. The whole glyph represents the length from the edge of the palm to the elbow, which is one foot.