When we say that a number is irrational, it is when this number consists of a never ending digits to the right of the decimal point. In this case, let us check the given values above. A. square root of 1 is still 1. B. square root of 9 is 3. C. square root of 25 is 5. D. square root of 50 is 7.07106781187. Therefore, the option that is irrational is option D. Hope this answer helps.
