Section 3.3 – Parallel Lines and Transversals

Transversal – a line, ray, or segment that intersects two or more coplanar lines, rays, or segments, each at a different point.

Alternate interior angles – 2 nonadjacent interior angles that lie on opposite sides of a transversal

Ex] and are alternate interior angles

Alternate exterior angles – 2 nonadjacent exterior angles that lie on opposite sides of a transversal

Ex] and are alternate exterior angles

Same-side interior angles (consecutive) – interior angles that lie on the same side of a transversal

Ex] and are same-side interior angles

Corresponding angles – 2 nonadjacent angles, one interior and one exterior, that lie on the same side of a transversal

Ex] and are corresponding angles

For 2 parallel lines cut by a transversal:

- Alternate interior angles are congruent

- Alternate exterior angles are congruent

- Same-side interior angles are supplementary

- Corresponding angles are congruent