Do Now 4/2/13Do Now 4/2/13 Take out HW from last night.Take out HW from last night.

Text p. 312, #1-16 all, 21Text p. 312, #1-16 all, 21

Copy HW in your planner.Copy HW in your planner. Text p. 318, Text p. 318, #10-23 all, 27 & 28#10-23 all, 27 & 28

In your journal, describe how to use a In your journal, describe how to use a protractor. Use step-by-step instructions on protractor. Use step-by-step instructions on how to measure an angle.how to measure an angle.

HomeworkHomework Text p. 312, #1-16 all, 21Text p. 312, #1-16 all, 21

1) Q, R, S1) Q, R, S 2)2) 3) plane QRS3) plane QRS 4) 4) 5) 5) 6) 6)

7) D, E, F7) D, E, F 8) 8) 9) plane DEF9) plane DEF

10) 10) 11) 11) 12) 12)

13) Plane ABC 13) Plane ABC contains points A, B, contains points A, B, C; lines AB & BC; line C; lines AB & BC; line segments AB, AC, & segments AB, AC, & BC; rays AB, BA, BC, BC; rays AB, BA, BC, CB, & CA. Plane ACD CB, & CA. Plane ACD contains points A, C, contains points A, C, D; line segments AC, D; line segments AC, AD, & CD; and ray CAAD, & CD; and ray CA

USUTUQ ,,

RTQS ,

CDAD

CEAE

BCBA

&

,&

,&

SURUQU ,,

EFFDDE ,,

EFDE,

CDFEEDAB

BDAEBCAF

&,&

,&,&

DFEFDE ,,

HomeworkHomework Text p. 312, #1-16 all, 21Text p. 312, #1-16 all, 21

14) 6; 14) 6; 15) answer vary15) answer vary

16)16)

21) C 21) C

,,,,,, YZXZXYWZWYWX

ObjectiveObjective

SWBAT identify angles and angle SWBAT identify angles and angle pairspairs

Angletwo rays with a common endpoint.

C

D

EVertexVertex

SidesSides

Section 8.2 “Classifying Section 8.2 “Classifying Angles”Angles”

Naming AnglesNaming Angles The following angle can be named in three The following angle can be named in three

ways: ways:

BB

CCAA

BAC ACABVertexVertex

Types of AnglesTypes of Angles Right angleRight angle = 90 degrees = 90 degrees

Acute angleAcute angle = less than 90 degrees = less than 90 degrees

Obtuse angleObtuse angle = more than 90 = more than 90 degreesdegrees

Straight angleStraight angle = exactly 180 = exactly 180 degreesdegrees

The The MEASUREMEASURE of is of is written as .written as .

AA PROTRACTORPROTRACTOR can be can be used to approximate the used to approximate the measure of an angle. measure of an angle.

AAm

Using a ProtractorUsing a Protractor

Find Find

BB

ABCm

AA

CC

= 130°

Using a ProtractorUsing a Protractor

Find Find

BB

ABCmAA

CC

= 70°

What is the measure of a What is the measure of a straight line (in degrees)? straight line (in degrees)?

CCAA

180180°°

B

Supplementary AnglesAngles When two angles form a straight When two angles form a straight line, the sum of their measures is line, the sum of their measures is 180180°°

CC

DD

EE

AA

180180°°

150150°° 3030°°

Complementary Angles Complementary Angles

When two angles form a right When two angles form a right angle, the sum of their measures angle, the sum of their measures is 90is 90°°

YY

ZZ

XX

WW

6464°°

2626°°

9090°°

Use the diagram to tell whether the angles are complementary, supplementary, or neither.

OMP and PMQ

O

N

P Q

R

M

60°30°

OMP = 60° and PMQ = 30° and 30°+60° = 90° therefore, they are complementary.

Use the diagram to tell whether the angles are complementary, supplementary, or neither.

NMO = 15° and OMR= 165° and 15°+165° = 180° therefore, they are supplementary.

O

N

P Q

R

M

NMO and OMR

15°15°165°165°

Use the diagram to tell whether the angles are complementary, supplementary, or neither.

BAC = 35° and EAF= 35° and 35°+35° = 70° therefore, they are neither.

C

B

D

E

F

A

35°35°35°35°

BAC and EAF

Finding Angle MeasuresFinding Angle MeasuresAngles A and B are complementary. If mA is 56°, what is the mB?

Since A and B are complementary, mA + mB = 90°.

mA + mB = 90°

56° + mB = 90°

– 56° – 56°

mB = 34°

Substitute 56° for mA.

Subtract 56° from both sides.

The measure of B = 34°.

Finding Angle MeasuresFinding Angle MeasuresAngles P and Q are supplementary. If mP is 32°, what is the mQ?

Since P and Q are supplementary, mP + mQ = 180°.

mP + mQ = 180°

32° + mQ = 180°

– 32° – 32°

mQ = 148°

Substitute 32° for mP.

Subtract 32° from both sides..

The measure of Q = 148°.

HomeworkHomework

Text p. 318, Text p. 318, #10-23 all, 27 & 28#10-23 all, 27 & 28