A rational number has a repeating decimal (for example, 1/3 (3.33...) or 1 (1.00...). A irrational number has a nonrepeating, neverending decimal (pi is 3.1415...)
Sqrt25 is equal to 5, so that's rational.
sqrt1.44 is equal to 1.2, and that's rational as well.
sqrt121 is equal to 11 - rational
However, sqrt17 is a neverending decimal equal to 4.1231056..., which makes it irrational.
Hope I helped!