Chapter 2

Points, Lines, and Angles

1

Goal

Tell type of angle. Label angles. Measure angles.

2

Review

3

4

A? B? C?

Check

a ) ray b) line segment c) line

5

6

7

angle a figure formed by the

intersection of two rays

8

angle

Rays are called sides.

Point where sides intersect is called a vertex.

9

angle examples non-examples

10

Naming angles

Method 1 angle x angle y

Method 2 angle ABC angle CBA

11

12

Degrees

List everything you can tell about this angle.

13

-Angle – 2 rays that intersect -Sides – rays- Point where rays intersect – vertex- Angle ABC or CBA-Measured in degrees- 60 degrees

14

Types of Angles

15

Right Angle

Right angle an angle whose measure is 90 degrees

16

17

right angles not right angles

18

Acute angle acute angle

• an angle• whose measure • is less than 90

degrees

19

20

acute angles not acute angles

21

obtuse angle

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

degrees but• less than 180 degrees

22

23

Obtuse angle

Why are these obtuse angles?

Obtuse Angles Not Obtuse

24

25

What type of angle? Why?

26

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

a.acuteb.right anglec.obtused.acutee.right anglef. obtuse

27

straight anglestraight angle an angle whose measure is 180 degrees

28

straight angles not straight angles

29

Page 28 number 1 - 101. measure of angle ARF

180 degreesstraight angle

2. measure of angle CRF120 degreesobtuse

3. measure of angle BRF155 degrees obtuse

30

adjacent angles adjacent angle

two angles have same vertex share one ray

31

List adjacent angles

Adjacent angles

32

List adjacent angles

Adjacent angles

33

adjacent angles not adjacent angles

34

Page 29 1.Angle CDB is adjacent to angle _____

2. Angle TUV is adjacent to angle ____

3. Angle SRP is adjacent to angle ____

35

vertical angles Vertical angles When two lines

intersect two pairs of

vertical angles are formed

36

vertical angles Vertical angles are NOT adjacent.

Vertical angles have the same measure.

37

Which angles are vertical?

38

Which angles are adjacent?

39

Page 30 Vertical angles 1. angle YPV and angle ____1. angle YPV and angle RPS2. angle QPR and angle _____3. angle QPR and angle VPT

40

complementary angles two angles sum of measures is 90 degrees

41

42

complementary angles What angles are complementary?

Why?

43

complementary angles Are these angles complementary?

Why or Why not?

44

complementary angles

not complementary angles

45

Supplementary angles two angles sum of measures is 180 degrees

46

Supplementary angles two angles sum of measures is 180 degrees

47

48

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

supplementary angles

not supplementary angles

49

Review of Angles

50

Page 31

51