Answer:
The answer is [tex]\sqrt{31}[/tex]
Step-by-step explanation:
In order to determine the answer, we have to know about rational and irrational numbers.
The rational numbers can be written as a ratio of two integers, that means, as a simple fraction. We know that the decimal numbers can be written as a fraction, so decimal numbers are rational numbers too.
The irrational numbers are real numbers that can not be written as a simple fraction. There are some special numbers that are irrational:
- root of prime numbers
- Pi number
- Euler's number
Analyzing the possible options:
A. It is a fraction, specifically, a mixed fraction. So it is rational number.
B. It is an irrational number because 31 is a prime number.
C. It is a finite decimal number, so we can express it as a fraction. Then it is a rational number.
D. It is a semi infinite decimal number, so we can express it as a fraction. Then it is a rational number.
Finally, the number that it is not rational is [tex]\sqrt{31}[/tex]
