Prove that the bisectors of two adjacent supplementary angles include a right angle.

In the given figure, $l \Vert m$ and a transversal $t$ cuts them. If $\angle 1=120°,$ find the measure of each of the remaining marked angles.

In the given figure, $l \Vert m$ and a transversal $t$ cuts them. If $\angle 7=80°,$ find the measure of each of the remaining marked angles.

In the given figure, $l \Vert m$ and a transversal $t$ cuts them. If $\angle 1:\angle 2=2:3,$ find the measure of each of the marked angles.

For what value of $x\mathit{ }$will the lines$\mathit{ }l\mathit{ }$and $m$ be parallel to each other?

For what value of $\mathrm{x}$ will the lines $l$ and $m$ be parallel to each other?

In the given figure, $AB\parallel CD$ and $BC\parallel ED$. Find the value of $x$.

In the given figure, $AB\parallel CD\parallel EF$. Find the value of $x$.

In the given figure, $AB\parallel CD$. Find the values of $x, y\mathit{ }$and $z$.