70 times 140 is the bath towel enough for adults? He is 6 feet tall and of medium build.

Yes, the conventional size of hotel and home bath towels is 70* 140cm, which is the conventional bath towel size, regardless of the height. Conventional sizes of towels are: 34*74cm, 35*75cm and 34*75cm. These three kinds of towels are all regular sizes. I suggest you consult Jingzhuyuan next time you buy a towel.