Question:
Represent $\sqrt{5}$ on the number line.
Solution:
To represent $\sqrt{5}$ on the number line, follow the following steps of construction:
(i) Mark points 0 and 2 as O and P, respectively.
(ii) At point A, draw AB ⊥ OA such that AB = 1 units.
(iii) Join OB.
(iv) With O as centre and radius OB, draw an arc intersecting the number line at point P.
Thus, point represents $\sqrt{5}$ on the number line.
Justification:
In right ΔOAB,
Using Pythagoras theorem,
$\mathrm{OB}=\sqrt{\mathrm{OA}^{2}+\mathrm{AB}^{2}}$
$=\sqrt{2^{2}+1^{2}}$
$=\sqrt{4+1}$
$=\sqrt{5}$