Yes, it is. You can simply input 4/7 in a calculator to see that the answer is
[tex] \dfrac{4}{7} = 0.571428571428571428\ldots[/tex]
In other words, the 6-period digits 571428 keep repeating after the decimal point: we write this as
[tex] \dfrac{4}{7} = 0.\overline{571428}[/tex]
