Mathematics — CBSE Class 10 board question

Option B: $\sqrt{4}$

$\sqrt{4} = 2$, which is a rational number. Since $\sqrt{3} \approx 1.732$ and $\sqrt{5} \approx 2.236$, the value $2$ lies between them.

• $\sqrt{4} = 2$ is a perfect square, hence rational (can be written as $\frac{2}{1}$).
• Options A and D are non-terminating, non-repeating decimals → irrational.
• Option C: $\sqrt{\frac{15}{4}} = \frac{\sqrt{15}}{2}$, which is irrational since $\sqrt{15}$ is irrational.
• Always check: is the number rational and does it fall between $\sqrt{3} \approx 1.732$ and $\sqrt{5} \approx 2.236$? Only $\sqrt{4} = 2$ satisfies both conditions.