Question

Classify the following as rational number and irrational number: 5.7

Answer 1

Definition:

1. Rational number: A rational number is a number that is expressed as $\frac{p}{q}$, where p and q are integers, and $q\ne 0$.

Ex. $2,\frac{1}{4},\frac{11}{7},...$

2. Irrational number: An irrational number is a number that cannot be expressed as $\frac{p}{q}$, where p and q are integers, and $q\ne 0$.

Ex.$\sqrt{2},\sqrt{3},\sqrt{11},...$

Given number is 5.7.

This number can be written in this way

$5.7=\frac{57}{10}$

Here, 57 and 10 are integers.

Thus, 5.7 can be written in the form of $\frac{p}{q}$, where p and q are integers, and $q\ne 0$.

Hence, 5.7 is a rational number.