Question

Which of the following is/are an irrational number?

• A. $\pi$
  
• B. $\sqrt{5}$
  
• C. $\sqrt{7}$
• D. $\frac{22}{7}$

Answer 1

Answer: (A), (B), (C)

The correct options are
A

$\pi$

B

$\sqrt{5}$

C

$\sqrt{7}$

$\pi$ is not a rational number and so are $\sqrt{5}$ and $\sqrt{7}$, square roots of prime numbers are always irrational.

$\pi$ is often mention as $\frac{22}{7}$, but it is not exactly $\frac{22}{7}$; It is approximated to be so. It is the ratio of circumference and diameter of a circle.

So, $\pi ,\sqrt{5}$ and $\sqrt{7}$ are irrational numbers.