Question

An irrational number is marked on the number line (D) as shown in the figure below. Find the value of D.

• A. $\sqrt{3}$
• B. $\sqrt{5}$
• C. $\sqrt{7}$
• D. $\sqrt{9}$

Answer 1

The correct option is B $\sqrt{5}$

By Pythagoras theorem we know that,

$A{C}^2=A{B}^2+C{B}^2$

$A{C}^2=(1{)}^2+(2{)}^2$

$A{C}^2=1+4$

$\Rightarrow AC=\sqrt{5}$

$\therefore$ The value of D is $\sqrt{5}$