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

In $\Delta ABC$,$\angle B = 70^{\circ}$ and $\angle C = 80^{\circ}$. The bisector of $\angle A$ intersects $BC$ at $D$. Find $\angle ADB$ and $\angle ADC$.

$\angle A$ and $\angle B$ are complementary angles. If $\angle A : \angle B = 1 : 5$,then find $\angle A$ and $\angle B$.

In the given figure,if $PQ \parallel RS$,$YZ \perp RS$ and $\angle SZX = 143^{\circ}$,then find $\angle PXZ$,$\angle XZY$ and $\angle YXZ$.

In the given figure,find the value of $x$ for which the lines $l$ and $m$ are parallel.

In the given figure,$POQ$ is a straight line. The value of $x$ is: (in $^{\circ}$)