[tex] \pi [/tex] is the only irrational number on the list. As a reminder, an irrational number is one which can't be written as a ratio of two integers.
With a little scratch work, we can show that [tex] 4.\overline{8} [/tex] can be written this way:
[tex] x = 4.\overline{8}\\10x=48.\overline{8}\\10x-x=48.\overline{8}-4.\overline{8}\\9x=44\\x=\frac{44}{9} [/tex]
And [tex] \sqrt{9}=3 [/tex], which can be written as a ratio like [tex] \frac{3}{1}, \frac{6}{2},\frac{9}{3} [/tex], or any other where the numerator is 3 times larger than the denominator.
A proof of the irrationality of [tex] \pi [/tex] is pretty involved and advanced, so you'll just have to take my word for it for now!
