### Theory:

Let us see some more pairs of angles, in this lesson.
1. Co-interior angles:

Each pair of angles named $$∠3$$ and $$∠6$$, $$∠4$$ and $$∠5$$ are marked on the same side of transversal line $$l$$ and are lying between the lines $$m$$ and $$n$$. These angles are lying on the interior of the lines $$m$$ and $$n$$ as well as the same side of the transversal line $$l$$. So these are called as co-interior angles.
2. Co-exterior angles:

Each pair of angles named $$∠1$$ and $$∠8$$, $$∠2$$ and $$∠7$$are marked on the same side of transversal line $$l$$ and are lying outside of the lines $$m$$ and $$n$$. These angles are lying on the exterior of the lines $$m$$ and $$n$$ as well as the same side of the transversal line $$l$$. So these are called as co-exterior angles.