Chapter 2

Points, Lines, and Angles

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Goal

Tell type of angle. Label angles. Measure angles.

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Review

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A? B? C?

Check

a ) ray b) line segment c) line

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angle a figure formed by the

intersection of two rays

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angle

Rays are called sides.

Point where sides intersect is called a vertex.

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angle examples non-examples

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Naming angles

Method 1 angle x angle y

Method 2 angle ABC angle CBA

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Degrees

List everything you can tell about this angle.

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-Angle – 2 rays that intersect

-Sides – rays

- Point where rays intersect – vertex

- Angle ABC or CBA

-Measured in degrees

- 60 degrees

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Types of Angles

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Right Angle

Right angle an angle whose measure is 90 degrees

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right angles not right angles

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Acute angle acute angle

• an angle• whose measure • is less than 90

degrees

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acute angles not acute angles

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obtuse angle

obtuse angle• an angle • whose measure is • greater than 90

degrees but• less than 180 degrees

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Obtuse angle

Why are these obtuse angles?

Obtuse Angles Not Obtuse

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What type of angle? Why?

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Why type of angle? A? B? C? D? E? F?

a.acute

b.right angle

c.obtuse

d.acute

e.right angle

f. obtuse

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straight angle

straight angle an angle whose measure is 180 degrees

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straight angles not straight angles

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Page 28 number 1 - 10

1. measure of angle ARF

180 degrees

straight angle

2. measure of angle CRF

120 degrees

obtuse

3. measure of angle BRF

155 degrees obtuse 30

adjacent angles

adjacent angle two angles have same vertex share one ray

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List adjacent angles

Adjacent angles

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List adjacent angles

Adjacent angles

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adjacent angles not adjacent angles

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Page 29 1.Angle CDB is adjacent to angle _____

2. Angle TUV is adjacent to angle ____

3. Angle SRP is adjacent to angle ____

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vertical angles

Vertical angles When two lines

intersect two pairs of

vertical angles are formed

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vertical angles

Vertical angles are NOT adjacent.

Vertical angles have the same measure.

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Which angles are vertical?

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Which angles are adjacent?

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Page 30

Vertical angles

1. angle YPV and angle ____

1. angle YPV and angle RPS

2. angle QPR and angle _____

3. angle QPR and angle VPT

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complementary angles two angles sum of measures is 90 degrees

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complementary angles

What angles are complementary?

Why?

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complementary angles

Are these angles complementary?

Why or Why not?

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complementary angles

not complementary angles

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Supplementary angles two angles sum of measures is 180 degrees

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Supplementary angles two angles sum of measures is 180 degrees

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Why are figure 1 and figure 2 both examples of supplementary angles?

supplementary angles

not supplementary angles

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Review of Angles

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Page 31

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