A
Lesson Plan Elements
Name:
Heather Wright
Date:
3.18.08
Subject:
6th Grade Math
Time:
60 minutes
Purpose of Lesson:
To teach students the proper use of protractors
EALR:
Objective:
Students will be able to identify and measure angles using a protractor
Materials/Technology/Media:
 Protractor (for each student)
 Journals for note taking
 Angle Worksheets D-R
 Document Camera/Projector
B
TIME
INTRODUCTION (Include a statement of the objective and check that students can
state the objective. Might also include hook, rationale, background knowledge, review
and assessment of pre-skills)
As we continue to prepare for the WASL this month, today we are going
to review the use of a new measuring tool: the protractor. Can anyone tell
me what we measure by using the protractor? Angles
Let’s take a brief minute and review the different types of angles.
 What is the definition on an angle?
 Where is a vertex located on an angle?
 What are the different types of angles? Can you define them?
 Show me an example of each type of angle in this room.
Now, if the type of angle is determined by it’s measure in degrees, then
our job today is to learn how to use a protractor to find an angles exact
measurement.
C
TIME INSTRUCTION
Pass out “Vocabulary” Worksheet and “Measuring an Angle” Worksheet for
students to take notes on throughout the lesson. (Worksheets E & F)
 Everyone should have a protractor in front of you. Please grab one and we
will name and label the parts.
Place “Worksheet D” underneath the document camera as you point to the parts of
the protractor. Fill out the “Vocabulary” worksheet, using the camera, as the
students follow along.
Parts of the Protractor
 Outer Scale-The numbers on the outer edge of the protractor
 Inner Scale-The numbers on the inner edge of the protractor
 Center Mark-Always at the middle of the Zero-Edge
 Zero-Edge-Always at the same level as the 0* mark
I DO:
Measuring an Angle (MODEL WITH AN ACTUAL PROCTRACTOR, USING
THE DOCUMENT CAMERA, AS YOU GO THROUGH EACH STEP), and guide
students as they fill in their “measuring an angle” worksheet.
 STEP 1: Determine if the angle is acute of obtuse before using the protractor
 STEP 2: Place the center mark of the protractor on the vertex of the angle
 STEP 3: Rotate the zero edge of the protractor to line up with one ray of the
angle and for the other ray of the angle to cross the protractors scale
 STEP 4: Read the measure of the angle of the ray that crosses the protractors
scale
Common Mistakes: (Place Worksheet J under document camera)
 Using the incorrect scale (inner vs. outer)
 The center mark is not on the vertex. This usually happens after rotating the
protractor. Make sure after rotating the protractor that the center mark is still
on the vertex.
 Counting the marks in the wrong direction. Pay attention to whether the
numbers are increasing or decreasing.

One at a time, place “worksheets K-N” on the document camera and have
students volunteer to explain their reasoning for the measurement of each
angle.
D
WE DO:


Pass out “Worksheet O”
Students can work with partners, and take turns in measuring the angles on
the worksheets.
 Walk around the classroom as students work
 After enough time has been provided to complete the worksheet, place
“Worksheet O” under the document camera”. Ask for volunteers to come up
and demonstrate how to use the protractor to measure random problems on
the worksheet.
 As students demonstrate at the front, the class will have a chance to critique
their technique as they watch through the document camera.
Pictures:
 Place photos (Worksheets P-R) under the document camera and have
students volunteer to find an angel on the photo, outline it with a
highlighter, name it, and measure it.
 This provides another opportunity for more students to come and
demonstrate their angle measuring abilities along with giving the class more
opportunities to watch and critique their technique.
YOU DO:
Pass out the final worksheet for students to work on individually, allowing them to
show what they know/understand from the lesson that was given. Once students
are finished, they can turn their worksheet in to be corrected.
E
F
Inner
Scale
Outer
Scale
ZeroEdge
Center
Mark
G
Step
One
Step Two
Step
Three
Step Four
H
Step 1) Determine if the angle is acute or
obtuse before
using the protractor.
I
Step 2) Place the center mark of the
protractor on the
vertex of the angle
Step 3) Rotate the zero-edge of the protractor
J
to line up with
one ray of the angle and for the other ray
of the angle to
cross the protractor's scale.
K
Step 4) Read the measure of the angle of the
ray that
crosses the protractor's scale.
Common Mistakes
1) Using the incorrect scale.
2) The center mark is not on the
vertex.
This usually happens after rotating
the protractor.
Make sure after rotating the
L
protractor that the center mark is
still on the vertex.
3) Counting the marks in the wrong
direction.
Pay attention to whether the numbers
are increasing or decreasing.
M
N
O
P
Q
Use you protractor to extend the lines and measure
each angle.
1
2
3
4
5
6
7
8
9
R
10
11
12
S
QuickTi me™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
T
QuickTime™ and a
TIFF (U ncompressed) decompressor
are needed to see this picture.
U
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
V