Radical 又
5 strokes
對
right hand 又 (52) + inch 寸 (104a) = correct 对
The basic meaning of this character is “facing towards” and it has also come to mean “line up”, “match up”, “to be correct” and “to treat” (a person in a certain way). It is also used as a measure word for pairs of objects.
[对手 (31) duìshǒu opponent]
[对了 (66) duì le correct (at last); aha!]

If, when you shake hands, you have your right hands lined up to the nearest inch, you will be doing it in the correct way. / The ghostly etiquette-guarding dwarf makes the class practice daily.