# 8.3.1 Lesson Plan angles

```Course: 7th Grade Math
DETAIL LESSON PLAN
Student Objective
7.G.5 Use facts about supplementary, complementary, vertical, and adjacent angles in a multi-step problem to write and solve
simple equations for an unknown angle in a figure.
Lesson
8.3.1 – Replacement Lesson
Angles and Pairs of Angles
Prior Knowledge
Review bellwork
Review homework
Anticipatory Set / Introduction
 TODAY, we will use those skills to help us classify different types of angles.
 “Angel” songs.
 Say… As an introduction to today’s lesson I would like to play a few songs. Listen to the songs and tell me what they all have
in common. Play pieces of songs that all mention the word “Angel”. Tell them not to shout out the answer because it may
take some a few songs before they figure it out. When ready, call on a student or have students answer together,
They all deal with _________? Answer: They all deal with “Angels!”
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Today, I have been inspired to title our lesson “The Angel of Angles”.
Display, “The Angel of Angles”
Where do we see Angles?
Well… Let’s see… Continue with PowerPoint.
Teacher Input
 Play Angel songs and show PowerPoint (The Angel of Angles) to introduce today’s lesson on angles.
 Pass out student notes.
 Define different types of angles: Right, Straight, Acute, Obtuse (Tree Map)
 Talk about how you measure and draw angles with a protractor.
 Move on to “Pairs of Angles”. Ask students how many a “pair” is. They should say 2.
 Discuss these pairs of angles: Complementary, Supplementary, Vertical, and Adjacent
Complementary Trick: Starts with a “C”. Draw a “C” on the board. The “C” can be turned into a number.
Supplementary Trick: Starts with a “S”. Draw a “S” on the board. The “S” can be turned into a number.
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Explain and demonstrate how to use what you have just learned about angles to find the measurements of missing angles.
Allow students to work the “you try” problems. (Independently)
Classwork: Practice sheets involving angles. (In Groups or Think, Pair, Share)
Assessment
Question students for understanding. Monitor students as they work on their classwork.
Closure
 What is an acute angle? Less than 90 degrees
 What is an obtuse angle? More than 90 degrees but not 180 degrees
 How many degrees is a straight line? 180
 How many degrees is a right angle? 90
 Complementary angles together equal how may degrees? (Think of corner) 90
 Supplementary Angles together equal how many degrees? (Think straight line) 180
 Vertical angles are _____________? Equal
 Describe what adjacent angle are. Angles that are next to each other. They share a side.
Student Notes
Angles
Lesson 8.3.1
Section 1 – Angle Types
Angle Types
Right Angle
Measures exactly 90&deg;
Straight Angle
Measures exactly 180&deg;
Acute Angle
Measures less than 90&deg;
Obtuse Angle
Measures greater than 90&deg;
Draw your own example of the following angles without a protractor:
Acute Angle
Right Angle
Straight Angle
Obtuse Angle
Section 2 – Measuring and Drawing Angles
Protractors have two sets of numbers going in opposite directions.
Be careful which ones you use!
When in doubt, think…
Should this angle be bigger or smaller than 90&ordm; ?”
1) Use a protractor to measure the following angles:
a.
This is an acute angle. We know that
acute angles are smaller than 90&deg;.
Which scale should we use to measure
our angle? top -or- bottom
What is the measurement?
b.
This is an obtuse angle. We know that
obtuse angles are bigger than 90&deg;.
Which scale should we use to measure
our angle? top -or- bottom
What is the measurement?
2) Draw the following angles using a protractor. Identify the type of angle you drew.
a. 75&deg;
b. 160&deg;
c. 90&deg;
Section 3 – Pairs of Angles
Complementary Angles – Two angles that add together to equal exactly 90&deg;
Tip! Complementary Angles make a Corner.
Supplementary Angles – Two angles that add together to equal exactly 180&deg;
Tip! Supplementary Angles make a Straight Line
Adjacent Angles – Angles that are next to one another.
They share a side.
A and
Vertical Angles – Angles that are across from one another (or opposite).
Vertical angles have equal measurements.
A and
B are vertical angles.
D and
C are vertical angles.
Angles and Pairs of Angles
Guided Practice
the missing measurements (m).
Example 1. Supplementary angles (180ᵒ)
Example 2. Complementary angles (90ᵒ)
m YNB = _________
m TNB = 106
m BTZ = _________
m ZTG = 49
Example 3. Vertical angles
m ZKF = 96&ordm;
m EKU
m UKF
m EKZ
= _________
= _________
= _________
Example 4 – Measuring Angles.
This is an obtuse angle. We know that obtuse angles are bigger than 90&deg;.
Which scale should we use to measure G? top -or- bottom
What is the measurement of G? Answer: __________
Angles and Pairs of Angles
You Try!
the missing measurements (m).
1.
2.
m SEN = _________
m ZEN = 148
m SGU = _________
m UGX = 29
3.
m
m
m
m
KTS = 81&ordm;
QTV = _________
KTQ = _________
VTS
= _________
4.
m W = _________
W
Name: ________________
Period: _____
Angles and Pairs of Angles
1) Classify each angle as acute, obtuse, right, or straight.
2) Find the measure of the complement of each angle.
3) Find the measure the supplement of each angle.
4) Use what you know about vertical and supplement angles to find each missing angle.
a) Name two angles adjacent to
BAF. ________ ________
b) Name two angles adjacent to
KAL. ________ ________
c) Name two angles adjacent to
JAM. ________ ________
Name: ___________________
Period: _______
1.
Angles and Angle Pairs
A
2.
A
B
m ∠ABC
C
B
m ∠Z
______________&deg;
Z
______________&deg;
3. Using what you know about angles to match each measurement to the correct angle.
30&ordm;
__________&deg;
90&ordm;
180&ordm;
__________&deg;
160&ordm;
110&ordm;
__________&deg;
4. What angle measure is complementary to 73&ordm;?
______________&deg;
5. What angle measure is supplementary to 56&ordm;?
______________&deg;
__________&deg;
__________&deg;
See Back
Use the diagram below to answer questions 6 – 11.
E
D
45&ordm;
45&ordm;
A
F
60&deg;
30&ordm;
B
C
6.
Which angle is obtuse?
A. ∠FBC
B. ∠DBA
C. ∠DBC
D. ∠EBC
7.
Which angle is acute?
A. ∠DBE
B. ∠ABC
C. ∠DBF
D. ∠CBE
8.
Which angle is complementary to ∠EBF ?
A. ∠DBE
B. ∠FBC
C. ∠DBF
D. ∠CBE
9.
Which angle is supplementary to ∠ABD ?
A. ∠ABC
B. ∠FBC
C. ∠DBF
D. ∠DBC
10. Name a straight angle?
∠____________________
11. Name two right angles?
∠____________________
12. Name an angle adjacent to ∠FBC ∠
∠____________________
____________________
Angles and Pairs of Angles
1) Classify each angle as acute, obtuse, right, or straight.
2) Find the measure of the complement of each angle.
3) Find the measure the supplement of each angle.
4) Use what you know about vertical and supplement angles to find each missing angle.
Angles and Angle Pairs
1.
A
2.
A
B
C
B
m ∠ABC __120&deg;___
Z
m ∠Z ___25&deg; __
3. Using what you know about angles to match each measurement to the correct angle.
30&ordm;
____30____&deg;
90&ordm;
___160____&deg;
180&ordm;
160&ordm;
110&ordm;
___180____&deg;
___110____&deg;
____90____&deg;
4. What angle measure is complementary to 73&ordm;? ___17____&deg;
5. What angle measure is supplementary to 56&ordm;? ___124___&deg;
See Back
Use the diagram below to answer questions 6 – 11.
E
D
60&deg;
45&ordm;
45&ordm;
A
6.
8.
F
30&ordm;
B
C
Which angle is obtuse?
A. ∠FBC
7.
Which angle is acute?
A. ∠DBE
B. ∠DBA
B. ∠ABC
C. ∠DBC
C. ∠DBF
D. ∠EBC
D. ∠CBE
Which angle is complementary to ∠EBF ?
A. ∠DBE
9.
Which angle is supplementary to ∠ABD ?
A. ∠ABC
B. ∠FBC
B. ∠FBC
C. ∠DBF
C. ∠DBF
D. ∠CBE
D. ∠DBC
10. Name a straight angle?