Arrowheads show lines are parallel. A straight line that cuts a pair of parallel lines is called an intersecting transversal ... angles that are equal. The lines make an X shape. Co-interior ...

On parallel lines, alternate (Z) angles are equal. On parallel lines, corresponding (F) angles are equal. On parallel lines, interior ... lines is called a transversal. Lines of equal length ...

The same principle works for interior ... angle mirroring the opposite side. This example occurs when two parallel lines are intersected by a third straight line. With both parallel lines cut ...