1-4 Pairs of Angles
Objectives
1. Identify adjacent angle and linear pair.
2. Identify and find measure of
Complementary and supplementary angles.
3. Identify and find measure of vertical angles
Holt McDougal Geometry
1-4 Pairs of Angles
Adjacent Angle &Linear Pair
Holt McDougal Geometry
1-4 Pairs of Angles
Adjacent Angle &Linear Pair
Example 1- Whether the indicated angles
are only adjacent, are adjacent and form a
linear pair, or are not adjacent.
 5 and  4
 1 and  4
 2 and  3
Holt McDougal Geometry
1-4 Pairs of Angles
Adjacent Angle &Linear Pair
You practice-Tell whether the indicated
angles are only adjacent, are adjacent and
form a linear pair, or are not adjacent.
 1 and  2
 1 and  3
2 and  4
2 and  3
Holt McDougal Geometry
1-4 Pairs of Angles
Complementary &Supplimentary
Holt McDougal Geometry
1-4 Pairs of Angles
Complementary &Supplimentary
• Tell whether each pair of labeled angles is
complementary, supplementary, or
neither.
•
4.
5.
Holt McDougal Geometry
1-4 Pairs of Angles
Complementary &Supplimentary
• Find the measure of each of the
following angles.
6.
7.
8.
9.
Complement of S _______
Supplement of S _______
Complement of R ______
Supplement of R ______
Holt McDougal Geometry
1-4 Pairs of Angles
Example 3: Finding the Measures of Complements
and Supplements
Find the measure of each of the following.
A. complement of F
B. supplement of G
HW
Holt McDougal Geometry
1-4 Pairs of Angles
You can find the complement of an angle
that measures x° by subtracting its measure
from 90°, or (90 – x)°.
You can find the supplement of an angle that
measures x° by subtracting its measure
from 180°, or (180 – x)°.
Holt McDougal Geometry
1-4 Pairs of Angles
DO NOW
Tell whether the angles are only adjacent,
adjacent and form a linear pair, or not
adjacent.
5 and 6
5 and 6 are adjacent angles. Their noncommon
sides, PT and PQ, are opposite rays, so 5 and 6 also
form a linear pair.
Holt McDougal Geometry
1-4 Pairs of Angles
DO NOW
Tell whether the angles are only adjacent,
adjacent and form a linear pair, or not
adjacent.
7 and 8
7 and 8 have a common vertex, P, but do not have
a common side. So 7 and 8 are not adjacent
angles.
Holt McDougal Geometry
1-4 Pairs of Angles
Warm Up
Simplify each expression.
1. 90 – (x + 20)
70 – x
2. 180 – (3x – 10) 190 – 3x
Holt McDougal Geometry
1-4 Pairs of Angles
Check It Out! Example 2
Find the measure of each of the following.
a. complement of E
(90 – x)°
90° – (7x – 12)° = 90° – 7x° + 12°
= (102 – 7x)°
b. supplement of F
(180 – x)
180 – 116.5° =
Holt McDougal Geometry
1-4 Pairs of Angles
Vertical Angles
Words
Two non-adjacent angles
formed by two intercepting
lines.
Holt McDougal Geometry
Drawing
equation
1-4 Pairs of Angles
Example 3: Identifying & Measuring Vertical Angles
A. Name the pairs of
vertical angles.
HML and JMK are vertical angles.
HMJ and LMK are vertical angles.
B. If mHML = 55°,
find mHMJ, mJMK, and mLMK
Holt McDougal Geometry
1-4 Pairs of Angles
HW: Pg 35, Ready to Go On
Holt McDougal Geometry