1. Parallel Lines and Transversals
Lesson 3.1

2. Parallel lines – coplanar lines that never intersect.
Parallel planes – planes that never intersect.
Transversal – A line that intersects 2 or more other lines.

3. Consecutive interior angles – one after the other on the 1 2 3 4
Consecutive interior angles –
one after the other on the
same side of t inside the lines.
(one on each line)
Alternate interior angles –
on opposite sides of t, inside
the lines. (one on each line) 5 6 7 8 t
Alternate exterior angles –
on opposite sides of t, outside
the lines. (one on each line)
Corresponding angles –
on the same side of t, in
corresponding positions.
(one on each line)

4. Skew Lines – lines that never intersect, are on different planes and are not parallel.