1st Method : √(2 × 2.5) = √5
Since there is no rational number whose square is 5. So √5 is irrational.
Also √ 2 × √ 5 is a irrational number.
2nd Method: 2.101001000100001.... is between 2 and 5 and it is non-recurring as well as non-terminating.
Also, 2.201001000100001......... and so on