Parallel Lines Cut by a Transversal

• A transversal is a line that intersects at least two other lines

• The two other lines, l₁ and l₂ in the diagram, could be parallel, but do not have to be

Write a definition for a transversal in your notes.

When lines are intersected by a transversal, multiple angles are created.

These angles are between the lines intersected by the transversal and are on opposite sides of the transversal.


Write a pair of alternate interior angles for the example on your notes.

These angles are outside the lines intersected by the transversal and are on opposite sides of the transversal.

Write a pair of alternate exterior angles for the example on your notes.

These angles are between the lines intersected by the transversal, but are on the same side of the transversal.

Write a pair of same side interior angles for the example on your notes.

These angles are located at the same position of each intersection, or the same "corner"

Write a pair of corresponding angles for the example on your notes.

All of these angle relationships have special properties (congruent, supplementary, etc) if the lines intersected by the transversal are parallel, which we will discuss when we have class next.

Thanks for following along today!