3.1 – Identify Pairs of Lines and Angles
Parallel Lines: two lines are parallel if they
do not intersect AND are coplanar
Skew Lines: Two lines are skew lines if they
do not intersect and ARE NOT coplanar.
Parallel Planes: Two planes are parallel if
they do NOT intersect.
3.1 – Identify Pairs of Lines and Angles
3.1 – Identify Pairs of Lines and Angles
Example 1:
Think of each segment in the figure as part of a
line. Which line(s) or plane(s) in the figure
appear to fit the description?
a. Line(s) // to Line CD and
containing point A
b. Line(s) skew to Line CD and
containing point A.
3.1 – Identify Pairs of Lines and Angles
Example 1:
Think of each segment in the figure as part of a
line. Which line(s) or plane(s) in the figure
appear to fit the description?
c. Line(s) perpendicular to Line CD
and containing point A.
d. Plane(s) parallel to plane EFG
and containing point A.
3.1 – Identify Pairs of Lines and Angles
PARALLEL AND PERPENDICULAR LINES
Through a point not on a line,
there are infinitely many lines.
Exactly one parallel.
Exactly one perpendicular.
3.1 – Identify Pairs of Lines and Angles
3.1 – Identify Pairs of Lines and Angles
Example 2:
The figure shows a swing set on a
playground.
Name a pair of perpendicular lines.
a. Name a pair of parallel line.
b. Is Line DH perp to Line LM? Explain?
3.1 – Identify Pairs of Lines and Angles
A transversal is a line that intersects two or
more coplanar lines at different points.
3.1 – Identify Pairs of Lines and Angles
Example 3:
Identify all pairs of angles of the given type.
a. Corresponding
b. Alternate Interior
c. Alternate Exterior
d. Consecutive Interior
3.1 – Identify Pairs of Lines and Angles
Example 4:
Classify the pair of numbered angles.
a.
b.
c.