Question

Which of the following is a rational number?

• A. √2
• B. ∏
• C. 2/0
• D. 4.8

Answer 1

The correct option is D

4.8

A rational number can be written in the form of $\frac{p}{q}$ where $p$ and $q$ are integers and $q$ is not equal to zero. Rational numbers have their decimal expansions as either terminating or non-terminating recurring. Otherwise, the number is irrational.

$\pi$ is the ratio of the circumference of a circle to its diameter and is usually approximated to $\mathrm{3.14159265358...},$ i.e., the digits do not terminate nor recur and hence, it is not rational.

$\sqrt{2}$ is approximated to $\mathrm{1.414213562373095...},$ i.e., the digits do not terminate nor recur and hence, it is not rational.

$\frac{2}{0}$ is not defined and for a rational number, the denominator should be non-zero.

$4.8$ on the other hand, satisfies all the properties of rational numbers.