Download Holt McDougal Geometry 1-4

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. Complement of S _______
7. Supplement of S _______
8.Complement of R ______
9.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