Represent $\sqrt{8.1}$ geometrically on the number line.

(N/A) $1$. Draw a line segment $AB = 8.1$ units on a number line.
$2$. From point $B$,mark a distance of $1$ unit and label the new point as $C$. Now,$AC = 8.1 + 1 = 9.1$ units.
$3$. Find the midpoint of $AC$ and label it as $O$.
$4$. Draw a semicircle with center $O$ and radius $OC$ (or $OA$).
$5$. Draw a line perpendicular to $AC$ at point $B$,which intersects the semicircle at point $D$. The length of $BD$ is $\sqrt{8.1}$.
$6$. With $B$ as the center and $BD$ as the radius,draw an arc that intersects the number line at point $E$. The distance $BE$ represents $\sqrt{8.1}$ on the number line.