When two coplanar lines are cut by a transversal, which condition does not guarantee that the two lines are parallel.

For two parallel lines and a transversal, $\mathrm{\angle }1=85°$. For which pair of angles measures is the sum least?

In Fig. find the values of $x$ and $y$.

In Fig. find $\angle d$.

In Fig. is $l\parallel m$?

In Fig. find the value of $x$ if $l\parallel m$.

In the adjacent figure, $l\parallel m$. Explain, why $\frac{x}{y}=1$.

Given $p\parallel q$ with transversal $t$, explain why $\angle 1$ and $\angle 3$ are supplementary?