Geometry: Intro to Angles (Lesson Plan)

I love teaching geometry. It’s the most fun of the math categories, in my opinion, since there’s so much geometry around us in the classroom every day! This is one way to introduce the basic types of angles. I’ve also used Bendarooz (wax sticks) to teach angles, but this lesson plan was from before I discovered those.


Context
Name: XXXXX                                  Date: March 25, 2009                         Grade level: 3rd           
Subject/topic: Angles                          Length/minutes: 20-30 minutes          Group size: whole class
Sequence: Introductory
Purpose
Standard/core: UtahStandard 3, objective 1, indicator d
Standard 3 Students will describe and analyze attributes of 2-dimensional shapes.
Objective 1Describe and compare attributes of 2-dimensional shapes
d.      Identify right angles in geometric figures, or in appropriate objects, and determine whether other angles are greater or less than a right angle.
Learning goal: Students will be able to identify right, obtuse and acute angles.
Major concepts:
Right angle: an internal angle which is equal to 90°
Obtuse angle: an internal angle which is greater than 90°
Acute angle: is an internal angle which is less than 90°
Angle: Two rays that share the same endpoint
Assessment
Given a worksheet with pictures, students will be able to identify angles with 100% accuracy.
Management
Self starter: none
Expectations: Sit and raise hands (no calling out); Students will focus on the topic; No sharpening pencils, getting out of seats going to the bathroom during the lesson.
Procedures: come back to desks when activity is over; raise hands to speak.
Fast finisher: make a list of things that have right angles.
Instructional Strategies

Attitude Orientation: (transition from lines lesson) We learned yesterday about lines, rays and points.  What happens when a line shares a point? Well…

Tell objective: “Today, are going to learn the about different angles.”
Schema Orientation: When you have two rays that share the same endpoint form an angle. How do you say “angle” in Spanish? (ángulo)
There are three basic kinds of angles…
Right angles:
            Put up word card that says “right angle” so students can see how the term is spelled.
            Draw a picture of a right angle.
Explain that when you draw a right angle, you can put a square I the corner to show that it has 90 degrees. You haven’t learned about degrees yet, but just know that there are 90 degrees in a right angle.
Have students stand up and make a right angle with their arms.
          put one arm out sideways
          then put your other arm straight up
Obtuse angles:
            Put up word card that says “obtuse angle” so students can see how it’s spelled.
            Draw a picture of an obtuse angle.
Explain that obtuse angles have more degrees than a right angle. They have to have more than 90 degrees to be obtuse angles.
Have students stand up and make a obtuse angle with their arms.
          put one arm out sideways
          then put your other arm leaning to the other side
Acute angles:
Put up word card that says “acute angle” so students can see that it’s an acute angle (not a cute angle).
            Draw a picture of an acute angle.
            Explain that acute angles are smaller than right angles, so they have less than 90 degrees.
Have students stand up and make a right angle with their arms.
          put one arm out sideways
          then put your other arm across the body to the side of the first arm
Activity: Now we’re going to go on an angle search. Pass out note cards and have students draw right angles in the corners.
Have students go around the room and use their note card to see if angles in the classroom are greater or smaller than the right angle on their note card.
Model how to compare the note card angle to something in the classroom such as a book, or edge of other supplies.
Check for understanding: Let the students have a few minutes to explore the angles in the classroom. Guide the class by having each student find a right angle, then an obtuse angle, and finally an acute angle. Have students find an angle and call on students to show the class their angle.
             
(Independent practice: Have students practice drawing angles.)
Assessment: pass out worksheet that asks students to label different angles as right, acute an obtuse.
Closure: Lead a class discussion about where you can see angles in everyday life.
Accommodations
            Visual learners- Power Point visuals, picture of the angles, drawing assessment
            ELL students- Modeling, word cards, picture of the angles
            Kinesthetic learners- use arms to make angles
           
Resources
Word cards
Notecards
Worksheet
Reflection
Step 1: (Instruction and Management) What went well? What should be improved?
Step 2: (Student Learning) What did the children learn? How do you know?
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