Question

Please help, not so good with this subject

Answer 1

I believe the answer is d

Explanation:

A rational number is a number that can be written as a ratio. That means it can be written as a fraction, in which both the numerator (the number on top) and the denominator (the number on the bottom) are whole numbers.

In this case, since
`√(81)` can be simplified to 9 and 9 can be written as a fraction (9/1) it is a rational number.