Section 3.1- Lines and Angles
Essential Question: What is the relationship between lines, angle pairs and planes?
Do Now:
Key Concept: Parallel and Skew
Definition
Parallel lines

Parallel lines are:

Symbol
Skew lines

Name a pair of skew lines
Skew lines are:
Parallel planes

Symbols
Name 2 pairs of parallel
lines
Planes that
Name a set of parallel
planes
Diagram
Example 1- Identifying Nonintersecting Lines and Planes
Angle Pairs Formed by Transversals
Alternate Interior Angles
Same-side interior angles
In this figure, line ___ is the transversal. It crosses lines
___ and ___.
Corresponding angles
Alternate exterior angles
Example 2- Identifying an Angle Pair
What are three pairs of corresponding angles?
Group Work:
1. Use the diagram to name each of the following. Assume the lines and planes that
appear to be parallel are parallel.
a. a pair of parallel planes
⃡
b. all lines that are parallel to 𝐴𝐵
c. all lines that are parallel to ⃡𝐷𝐻
d. two lines that are skew to ⃡𝐸𝐽
2. Identify all pairs of each type of angles in the diagram. Name the two lines and the
transversal that form each pair.
a. corresponding angles (1 pair)
b. alternate interior angles (2 pairs)
c. same-side interior angles (1 pair)
d. alternate exterior angles (1 pair)
HW: p. 144-145 #21-24, 30-35, 37-42, 53-55, 57-60