Question

Which of the following number's square root is not a rational number?

• A. 4
• B. 7.29
• C. 0.64
• D. 7

Answer 1

The correct option is D 7

We have,
$\sqrt{4}=2$
$\sqrt{7.29}=\sqrt{\frac{729}{100}}=\frac{27}{10}=2.7$
$\sqrt{0.64}=\sqrt{\frac{64}{100}}=\frac{8}{10}=0.8$
$\sqrt{7}=\mathrm{2.64575......}$ is neither reccurring nor terminating. So,$\sqrt{7}$ is an irrational number, where as all others are terminating and hence rational numbers.
Therefore, square root of 7 is not a rational number.