If two lines intersect each other,then the vertically opposite angles are.........

In the given figure,find the values of $x$ and $y$ and then show that $PQ \parallel XY.$

The sum of the three angles of a triangle is $\ldots \ldots \ldots$ (in $^o$)

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

In the figure,$DE \parallel QR$ and $AP$ and $BP$ are bisectors of $\angle EAB$ and $\angle RBA$ respectively. Find $\angle APB.$ (in $^{\circ}$)

The sum of a linear pair of angles is always.......... (in $^{\circ}$)