Download Lines and Angles

Geometry (Holt 3.1)
K.Santos
Lines and Planes
Parallel Lines—lines that are coplanar and do not intersect.
(can be segments and/or rays also)
Perpendicular lines—lines that intersect at 90° angles.
Skew lines—are lines that are not coplanar.
Skew lines are not parallel and do not intersect
Parallel planes—planes that do not intersect
Example: Lines and Planes
Parallel Lines:
𝐴𝐵 || 𝐶𝐷
A
C
B
D
Perpendicular Lines:
𝐶𝐷 ⊥ 𝐷𝐻
E
F
Skew Lines:
𝐴𝐵 and 𝐷𝐻
G
Parallel Planes:
plane ABD and plane EFH
H
Identifying Angles
 Transversal—a line that intersects two coplanar




lines at distinct points
Interior points— “inside” points
Exterior points— “outside” points
Alternate—on different sides of transversal
Same-side—on the same side of the transversal
(also known as consecutive)
a
t
b
Angle Pairs
1 2
3
m
4
n
5 6
7 8
p
Angle Pairs
 Alternate interior angles—pair of nonadjacent interior angles on




different sides of the transversal
< 3 and < 6
and
<4 and < 5
Alternate exterior angles—pair of nonadjacent exterior angles on
different sides of the transversal
< 1 and <8
and
<2 and <7
Same-side interior angles—pair of nonadjacent interior angles on the
same side of the transversal
<3 and <5
and
<4 and <6
Same-side exterior angles—pair of nonadjacent exterior angles on the
same side of the transversal
<1 and < 7
and
<2 and <8
Corresponding angles—a pair of nonadjacent angles on the same side
of the transversal, 1 interior with 1 exterior
<1 and <5
<2 and <6
<3 and <7
and
<4 and <8
Identify angle pairs and transversals
Use the diagram to identify the transversal and classify each angle pair.
o
4
1 2
3
5
6
<1 and < 3
line 0, corresponding angles
<2 and <6
line n, alternate interior angles
<4 and <6
line m, alternate exterior angles
<2 and <5
line n, same-side interior angles
m
n