Page 38 - Math Course 2 (Book 2)

Lines and Angles
Mo. 8

Lesson 1 interior angles
Interior angles lie inside the parallel lines.
∠C, ∠F, ∠D, ∠E

KEY CONCEPTS:
1. Identify the relationships of angles formed
by two parallel lines and a transversal.
2. Identify the relationships of vertical, Line 1 A B
adjacent, complementary, and C D
supplementary angles.
interior angles interior angles

Line 2 E F
MO. 8 - L1a G H

Angles Formed by Parallel Line 3 : The Transversal
Lines and a Transversal

Vocabulary A-Z exterior angles

Let us learn some vocabulary Exterior angles lie outside the parallel lines.
∠A , ∠H, ∠B , ∠G

parallel lines Exterior angles
In geometry, two lines on the same plane
(coplanar) that never intersect are parallel lines. Line 1 A B
C D
m
n
Line 2 E F
Line m and n are Parallel lines have G H
parallel. Using no point of Exterior angles
symbols, m || n. intersections.
Line 3 : The Transversal
transversal

When two parallel lines are intersected by a third alternate interior angles
line, this intersecting third line is called a Alternate interior angles are on opposite sides of
transversal, Eight angles are formed. the transversal and inside the parallel lines.

∠C and ∠F
transversal ∠D and ∠E

1 2 Line 1 A B
4 3 C D
interior angles interior angles
5 6
8 7 Line 2 E F
G H
Arrowheads are often
used in figures to
indicate parallel lines. Line 3 : The Transversal

30