In this example, there is a pattern in your numbers, but it’s not a repeating pattern.
Rational numbers have repeating patterns, like 0.9898989898989898… where it’s just 98 over and over.
Irrational number do not have a repeating pattern.
In your number, there’s one more 8 each time, so 98, then 988, then 9888, then 98888, and so on. So it’s not repeating. Because it’s not repeating, you know it’s irrational.
