Holt McDougal Geometry

1-4 Pairs of Angles

Objectives1.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 PairExample 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 PairYou 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 32 and 42 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

Find the measure of each of the following.

Example 3: Finding the Measures of Complements and Supplements

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

5 and 6

Tell whether the angles are only adjacent, adjacent and form a linear pair, or not adjacent.

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

7 and 8

Tell whether the angles are only adjacent, adjacent and form a linear pair, or not adjacent.

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 UpSimplify each expression.

1. 90 – (x + 20)

2. 180 – (3x – 10)

70 – x

190 – 3x

Holt McDougal Geometry

1-4 Pairs of Angles

Check It Out! Example 2

a. complement of E

Find the measure of each of the following.

b. supplement of F

= (102 – 7x)°

180 – 116.5° =

90° – (7x – 12)° = 90° – 7x° + 12°

(90 – x)°

(180 – x)

Holt McDougal Geometry

1-4 Pairs of Angles

Words Drawing equation

Two non-adjacent angles formed by two intercepting lines.

 

 

   

Vertical Angles

Holt McDougal Geometry

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 mHML = 55°, find mHMJ, mJMK, and mLMK

Holt McDougal Geometry

1-4 Pairs of Angles

HW: Pg 35, Ready to Go On