I’ve already taken you through the steps, if you’re still confused, do some research on your own.
Are you still demanding to refuse to acknowledge people are looking for body fat PERCENTAGE, and they are ultimately disinterested in body volume when doing this procedure?
The question is not the goal, but what they are measuring by immersing someone in water.
Weight can certainly be measured by floating an object and measuring the displacement, but this is not the reason for using water. A halfway decent digital scale will give weight to a fraction of an ounce without requiring a person to get wet.
The reason for using immersion is to measure volume.
I do enjoy these discussions, however. I haven't had so much fum since someone argued that 1^720 was a really big number and that a circle is not an ellipse.