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Geometry CP, Oct 3
Parallel Lines and Transversals
Book Section: 3-1
Essential Question: What are parallel lines, skew lines, and transversals
and how can I use them?
Standards: G-1.2, G-1.3, G-1.5, G-1.7, G-1.8
Basic Definitions
• Parallel lines – Coplanar lines that do not
intersect.
• Parallel planes – Planes that do not intersect
• Skew lines – Lines that do not intersect and are
not coplanar
• Transversal – A line that intersects two or more
coplanar lines at two different points.
Example – Parallel Lines
Notation
Transversal
You are told lines are parallel, or that fact is indicated by
‘arrows.’ Never assume that lines are parallel.
Example – Parallel Planes & Skew Lines
Examples
All segments parallel to JP
A segment skew to KL
A plane parallel to PQR
A plane parallel to JLR
Transversal Angle Relationships
When two lines are intersected by a transversal, a
myriad of angle relationships are formed:
• Interior angles
• Exterior angles
• Consecutive interior angles
• Alternate interior angles
• Alternate exterior angles
• Corresponding angles
Transversal Angle Relationships
Definitions and examples:
Examples
Examples
More Examples
Name the relationship between each pair of angles:
1) 2 and 6
5) 4 and 7
2) 3 and 5
3) 3 and 8
4) 1 and 7
Examples
Classwork: Text p. 176, 13-15, 31-36
Homework: HW Due 10 5, 1-20