1. Relationships Between Lines
Parallel Lines – two lines that are coplanar and do not intersect
Skew Lines – two lines that are NOT coplanar and do not intersect
Perpendicular Lines – two lines that intersect to form a right angle
Parallel Planes – two planes that do not intersect

2. Parallel and Perpendicular Postulates*
Postulate 13: Parallel Postulate
If there is a line and a point not on the line, then there is exactly one line through the point parallel to the given line.
Postulate 14: Perpendicular Postulate
If there is a line and a point not on the line, then there is exactly one line through the point perpendicular to the given point. l P * l

3. Transversals
A transversal is a line that intersects two or more coplanar lines at different points.

4. Angles Formed By Transversals
Corresponding Angles – two angles are corresponding if they occupy corresponding positions as a result of the intersection of the lines. (1 & 5)
Alternate Exterior Angles – two angles are alternate exterior if they lie outside the two lines on opposite sides of the transversal (1 & 7)
Alternate Interior Angles – Two angles that lie between the two lines on opposite sides of the transversal (4 & 6)
Consecutive Interior Angles – two angles that lie between the two lines on the same side of the transversal (4 & 5)
Who can name another pair for each of the angle types above?