Represent $\sqrt{20}$ on the number line.

(N/A) To represent $\sqrt{20}$ on the number line,we can use the Pythagorean theorem: $a^2 + b^2 = c^2$.
We can express $20$ as $4^2 + 2^2 = 16 + 4 = 20$.
$1$. Draw a number line and mark a point $O$ at $0$ and a point $A$ at $4$ units from $O$.
$2$. At point $A$,draw a perpendicular line segment $AB$ of length $2$ units.
$3$. Join $O$ and $B$. By the Pythagorean theorem,the length of $OB$ is $\sqrt{4^2 + 2^2} = \sqrt{16 + 4} = \sqrt{20}$.
$4$. Using a compass with center $O$ and radius $OB$,draw an arc that intersects the number line at point $P$.
$5$. The point $P$ represents $\sqrt{20}$ on the number line.