Question

What are co-interior angles?

Answer 1

The co-interior angles.

Co-interior angles are pairs of angles whose sum is equal to $180°$ which are between two parallel lines ,formed by respective parallel lines and transversal lines crossing them and at the same side of the transversal line.

The position of the interior angle between two lines re shown below:

Here, $\angle 3\&\angle 6$ and $\angle 4\&\angle 5$ are two pairs of the co-interior angles