A line segment has _______ end points.

11. Which of the following steps is INCORRECT while constructing an angle of  ${60}^0$?

Step-$1$: Draw a line $EF$ and mark a point $O$ on it.

Step-$2$: Place the pointer of the compass at $O$ and draw an arc of convenient radius which cuts the line $EF$ at point $P$.

Step-$3$: With the pointer at $A$ (as centre), draw an arc that passes through $O$.

Step-$4$: Let the two arcs intersect at $Q$. Join $OQ$. We get $\angle QOP$ whose measure is ${60}^0.$

Arrange the given steps in CORRECT order of constructing a perpendicular using ruler and compasses.

Steps of construction:

$1.$ With $A$ and $B$ as centres and a radius greater than $AP$ construct two arcs, which cut each other at $Q$.

$2.$ Join $PQ$. Then $\overleftrightarrow{PQ}$ is perpendicular to $l$. We write $\overleftrightarrow{PQ}\perp l$ .

$3.$ With $P$ as centre and a convenient radius, construct an arc intersecting the line $l$ at two points $A$ and $B$.

$4.$ Given a point $P$ on a line $l$.