Do Now 4/2/13

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# Do Now 4/2/13 - PowerPoint PPT Presentation

Do Now 4/2/13. Take out HW from last night. Text p. 312, #1-16 all, 21 Copy HW in your planner. Text p. 318, #10-23 all, 27 &amp; 28 In your journal, describe how to use a protractor. Use step-by-step instructions on how to measure an angle. 1) Q, R, S 2) 3) plane QRS 4) 5) 6)

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Do Now 4/2/13

• Take out HW from last night.
• Text p. 312, #1-16 all, 21
• Copy HW in your planner.
• Text p. 318, #10-23 all, 27 & 28
• In your journal, describe how to use a protractor. Use step-by-step instructions on how to measure an angle.
1) Q, R, S

2)

3) plane QRS

4)

5)

6)

7) D, E, F

8)

9) plane DEF

10)

11)

12)

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

Homework Text p. 312, #1-16 all, 21
Objective
• SWBAT identify angles and angle pairs
Section 8.2 “Classifying Angles”

Angle

two rays with a common endpoint.

D

Sides

C

Vertex

E

Naming Angles
• The following angle can be named in three ways:

B

C

A

Vertex

Types of Angles
• Right angle = 90 degrees
• Acute angle = less than 90 degrees
• Obtuse angle = more than 90 degrees
• Straight angle = exactly 180 degrees
The MEASURE of is written as .
• APROTRACTORcan be used to approximate the measure of an angle.
Using a Protractor
• Find

= 130°

A

C

B

Using a Protractor
• Find

= 70°

A

C

B

Supplementary Angles

When two angles form a straight line, the sum of their measures is 180°

D

180°

150°

30°

A

C

E

Complementary Angles

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

W

90°

64°

Z

26°

X

Y

P

Q

O

N

R

M

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

OMP and PMQ

30°

60°

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

P

Q

O

N

R

M

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

NMO and OMR

165°

15°

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

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

D

E

C

F

B

A

BAC and EAF

35°

35°

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

Finding Angle Measures

Angles A and B are complementary. If mA is 56°, what is the mB?

Since A and B are complementary, mA + mB = 90°.

mA + mB = 90°

56° + mB = 90°

Substitute 56° for mA.

Subtract 56° from both sides.

– 56° – 56°

mB = 34°

The measure of B = 34°.

Finding Angle Measures

Angles P and Q are supplementary. If mP is 32°, what is the mQ?

Since P and Q are supplementary, mP + mQ = 180°.

mP + mQ = 180°

32° + mQ = 180°

Substitute 32° for mP.

Subtract 32° from both sides..

– 32°– 32°

mQ = 148°

The measure of Q = 148°.

Homework

• Text p. 318, #10-23 all, 27 & 28