Geometry Line Vocabulary

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The students will be able to draw and identify lines in preparation to classify two-dimensional figures into categories based on their properties

Big Idea

The more students are exposed to new vocabulary the more they will use it and retain it.


In this lesson I introduce my students to the vocabulary of lines;  point, line, line segment, ray, angle and plane.  In order for my students to have precise mathematical conversations (MP6), they need to develop and use a basic geometric vocabulary. 

I also have my student note this vocabulary into a flip book because it is fun and very visual for them. They need to create a vocabulary resource that can be easily used.  I have them use a note-taking approach, because I also know that as my students get older note taking is an important skill. This is only the first step in exposing my students to new vocabulary.  I continue on with using the words as their spelling words, create word searches, drawings in homework and putting the words into writing.








Inclusion - Engaging Students in Their Learning

3 minutes

I start my lessons with an inclusion question to motivate and activate students learning.  Today I ask my students, "What do you know about a straight line - other than we need to practice lining up in a straight line for lunch?" 

Because I have a multiage classroom of fourth and fifth grade students, my fifth graders are trying to remember what they had learned last year about lines and the fourth grade students are pointing out the basics of a line.  I start to hear comments such as:

Isn't there a dot on a line?  What's that called again?

I can't draw a straight line without a ruler.

I remember the word ray for some reason.  Oh you remember that because it is half of an angle.  This student then draws an angle with an endpoint connecting two rays and students then go on to discuss right, acute and obtuse angles. 

Inclusion is meant to activate prior knowledge and to engage the students in the lesson by helping all students to feel included.  There are no wrong answers during this time, but I do not allow what I call from left-field discussion - off topic. 

I do not interrupt if I hear a student who has a misconception - at this point - I take a mental note to be sure the misconception is cleared up during the lesson. 


Line Vocabulary Explained

20 minutes

It is important for students to work on their mathematical communication skills by using clear and precise language in their discussions with others and in their own reasoning (MP6).  Because fifth graders are off to middle school in a short period of time, I know how important it is for them to be able to take notes - accurate notes. 

Begin by having your students place four pieces of paper in a stack, slide each paper down so they are about an inch apart and then fold so all pages create a flap.  When they fold the papers over, the lowest one an inch above the bottom papers.  Student example of folding flip book.

Have your  students title the  cover Geometric Lines.  Each flap should be titled Point, Line, Line Segment, Ray, Angle and Plane.  Under each flap they divide the section up into four sections: Example, Definition, Symbol, and Read - Flip Book Inside.  Each flap has a drawing of the example.

To reinforce each of the vocabulary words have your students write the word, a definition, a symbol and how the symbol world be read verbally.  This gives students a "a pocket dictionary" of the terms to be used.

You will see I have had my students either put the symbol on the bottom or the word.  It works well either way. To get the information to my students I write on the board each of the examples for them to copy.  See the pictures for examples.

Example Lines Vocab

Remember the important part of this lesson is to expose your students to new vocabulary and to give them a tool, the flip book, for organizing information.  Students will be immersed in geometry vocabulary through activities, homework and spelling. 


Line Flip Book Student Work

Line Example student work












Continuing to Practice

15 minutes

There are quite few ways I have my students practice their vocabulary but one fun way is to have one student say the vocabulary word and they toss a koosh, or some object, to another students to give the definition.  Another is two have two sets of index cards - one with the vocabulary word and another with the definition - students flip over and read the card.  Another student with the matching definition reads their definition.  This could be done with some having the words and others the definitions or mix it up with both words and definitions being passed out. 

I also like to send my students outside my room to look for the words in the "real outside." You can send your students out with their flip books and they can add sketches from where they find examples outside the classroom.  I had my students put the sketches in their Math Journals. This picture of student work is from a different set of geometry vocabulary words but will give you the idea -  Lines in our world

Students Finding Lines 2

Students Finding lines 3

I also included having students find the vocabulary words in pictures with their homework.