Calculations skinfolds

Well, I do not know if I can ask for help in relation to the calculation, but anyway, my question is:

I need to do the skinfold calculation, in this case the calculation of Pollok 3 folds, I researched the internet, but it is not so easy to understand, I wonder if the way I'm doing this is correct. I was just going to post the calculation, but I also did an executable example (very simple example) to be able to illustrate the situation better.

I used this information as a basis:

Para 3 dobras:
DC= 1,10938 – 0,0008267 (X2) + 0,0000016 (X2)
2 – 0, 0002574 (X3)
Legenda:
DC= Densidade Corporal em g/ml    
X2 = soma das 3 dobras (tórax, abdominal e coxa)
X3 = idade em anos 

Note: page 36: link

Code:

import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;

public class DobrasCuteneas extends JFrame {

    JTextField campoPeitoral = new JTextField();
    JTextField campoAbdominal = new JTextField();
    JTextField campoCoxa = new JTextField();
    JTextField campoGorduraIdeal = new JTextField();
    JButton botao = new JButton("Calcular");

    public DobrasCuteneas() {
        setTitle("Exemplo");
        add(tela());
        pack();
        acaoBotao();
        setLocationRelativeTo(null);
        setDefaultCloseOperation(EXIT_ON_CLOSE);

    }

    private void acaoBotao() {
        botao.addActionListener((ActionEvent ae)
                -> {
            calculo();
        });
    }

    private JPanel tela() {
        JPanel painel = new JPanel();
        JLabel label01 = new JLabel("Peitoral:");
        painel.add(label01);
        painel.add(campoPeitoral);
        campoPeitoral.setPreferredSize(new Dimension(100, 20));
        JLabel label02 = new JLabel("Abdominal:");
        painel.add(label02);
        painel.add(campoAbdominal);
        campoAbdominal.setPreferredSize(new Dimension(100, 20));
        JLabel label03 = new JLabel("Coxa:");
        painel.add(label03);
        painel.add(campoCoxa);
        campoCoxa.setPreferredSize(new Dimension(100, 20));
        painel.add(botao);
        botao.setPreferredSize(new Dimension(90, 20));
        JLabel label04 = new JLabel("Gordura ideal:");
        painel.add(label04);
        painel.add(campoGorduraIdeal);
        campoGorduraIdeal.setPreferredSize(new Dimension(100, 20));
        add(painel);

        return painel;
    }

    private void calculo() {
        float peitoral = Float.valueOf(campoPeitoral.getText().replaceAll(",", "."));
        float abdominal = Float.valueOf(campoAbdominal.getText().replaceAll(",", "."));
        float coxa = Float.valueOf(campoCoxa.getText().replaceAll(",", "."));
        float idade = 25;
        Float x2 = (peitoral + abdominal + coxa);

        Float densidadeCorporal = (float) (1.10938 - x2) + (x2 * 2) - idade;
        System.out.println("Densidade corporal: " + densidadeCorporal);
        Float percentualGordura = ((float) ((4.95 / densidadeCorporal) - 4.50) * 100);
        System.out.println("Percentual de gordura: " + percentualGordura);
        campoGorduraIdeal.setText("" + percentualGordura);
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(()
                -> {
            DobrasCuteneas dobras = new DobrasCuteneas();
            dobras.setVisible(true);
        });
    }
}

And for the final calculation (ideal fat):

%G = [(4,95/Densidade Corporal) - 4,50] x 100