$A$ part of a line with one end point is called a $\ldots \ldots \ldots .$

$\angle PQR$ and $\angle PQS$ are a linear pair of angles. If $11 \angle PQR = 9 \angle PQS$,then find $\angle PQR$ and $\angle PQS$.

Can a triangle have two obtuse angles? Give reason for your answer.

$AP$ and $BQ$ are the bisectors of the two alternate interior angles formed by the intersection of a transversal $t$ with parallel lines $l$ and $m$ (see figure). Show that $AP \parallel BQ$.

If one of the angles of a triangle is $130^{\circ},$ then the angle between the bisectors of the other two angles can be (in $^{\circ}$)

In the figure,$BA \parallel ED$ and $BC \parallel EF.$ Show that $\angle ABC + \angle DEF = 180^{\circ}.$