What are teh three ways to assess a person's body mass?

Question

I already know:
-height weight charts
-body mass index

but what is the other one?

Answer 1

The third one would be skinfold thickness measurements also known as body fat calipers. This requires the use of a pincher type tool.

Some other less used methods are:
underwater weighing
computerized tomography
dual-energy x-ray absorptiometry
bioelectrical impedance
These are less well known and require specially trained people to administer. They are also price prohibitive.