PIE*konkの「吊るす」が語源で、語源的にはhingeと同じ。
'To get the hang of a thing,' is to get the knack, or habitual facility of doing it well. A low expression frequently heard among us. In the Craven Dialect of England is the word hank, a habit; from which this word hang may perhaps be derived. [John Russell Bartlett, "Dictionary of Americanisms," New York, 1848]