Answer:
A. √10
Explanation:
A rational number can be written as the ratio of two integers
A. √10
This cannot be simplified into the ratio of two integers, Square roots that cannot be simplified are irrational
B. -√81
- 9
-9/1 which is the ratio of two integers so it is rational
c. 5/4
This is the ratio of two integers so it is rational
d. 9.12
912/100
This is the ratio of two integers so it is rational