6th Grade Math : Unit #8 - Geometry : Lesson #8

Classifying 3D Figures

Objective: SWBAT: • Define and identify edges, faces, and vertices on 3D figures • Identify and classify prisms, pyramids, and curved solids.
Standards: 6.G.A.4 MP3 MP6 MP7
Subject(s): Math
60 minutes
1 Do Now - 5 minutes

See my Do Now in my Strategy folder that explains my beginning of class routines.

Often, I create do nows that have problems that connect to the task that students will be working on that day.  Today I want students to think about what they already know about the words “three-dimensional” and “3D”.  Some students may think about 3D movies while other students may mention length, width, and height.  

I call on a student to share one idea.  That student then calls on the next student to share his/her idea.  I encourage students to build on what their classmates have said by using sentence starters like, “I agree/disagree with __________ because…” and “My idea connects with ____________’s idea…”  Students are engaging in MP3: Construct viable arguments and critique the reasoning of others.

2 Question - 5 minutes

I read over the definition and the question.  I tell students that they can jot down short observations rather than writing complete sentences.  Students may not be familiar with vocabulary words that help them describe the similarity and differences between these two figures and that is okay.   We will revisit this question at the end of the lesson.  I quickly call on a few students to share out observations.  

3 Learn Zillion Video - 10 minutes

I give students a minute to preview the video notes before we begin.  Students fill out the notes as we watch the video.  I frequently pause the video so students have time to fill in their notes.

Students work on the guided practice questions independently.  Students participate in a Think Pair Share about their answers.  I call on students to share out their answers.  I ask, “What is the difference between a pyramid and a prism?”  I want students to be able to define prism and pyramid.  I stress that a prism is made up of faces that are polygons.  

4 Classifying 3D Figures - 20 minutes


  • Before this lesson I Create Heterogeneous Groups. 
  • For this lesson I have a set of 3D figures for each group.  Here is an example
  • I Post A Key of the 3D figures chart.

I introduce the task to the students.  I show them the “Naming Three-Dimensional  Figures” sheet.  I pick out the cube (which I labeled as figure 1).  I call on students to ask and answer the questions on the sheet.  I ask a student to define “congruent”.  Once we have identified it as a cube, I ask for volunteers to identify and count the faces, edges, and vertices.   

I review expectations and announce groups.  I pass out the materials to groups.  As students work I walk around and monitor student progress and behavior.  I take note of figures that multiple groups are struggling to classify. 

If students are struggling I encourage them to use their notes and the “Naming Three-Dimensional Figures” sheet.  Students have all the resources they need to determine each figure’s name and characteristics.  Students are engaging in MP3: Construct viable arguments and critique the reasoning of others and MP6: Attend to precision.

When a group completes the chart, they raise their hands.  I quickly scan their work.  If they are on track, I send them to check with the key.  If there are problems, I tell students what they need to revise.  If students successfully complete the chart they can work on the extra practice. 

What is this 3D figure?
Discourse and Questioning

This video is an example of how I responded when a student asked me “What is this 3D figure?”  I guided her through using her “Naming 3D Figures” sheet as a resource.  After watching the video, I realize it would have been more meaningful if I asked the student “How do you know those are the bases?” or “Why aren’t the rectangular faces the bases?”  rather than giving her the definition of bases.  That way I could have more fully understood her thinking and known whether she just guessed that the hexagon faces were the bases.

5 Closure and Ticket to Go - 10 minutes

I have students flip to the Closure problem.  I read the prompt and remind students that they now should be able to use specific vocabulary words to describe the similarities and differences.  Students participate in a Think Pair Share.  I call on students to share their ideas.  I push students to be as specific and precise as possible with their observations.  I want students to be able to explain that figure A is a prism while figure B is a pyramid.  Although the names of these figures are not on the naming sheet I push students to come up with names before I tell them the names.  Students are engaging in MP3: Construct viable arguments and critique the reasoning of others, MP6: Attend to precision, and MP7: Look for and make sense of structure.

I pass out the Ticket to Go and the HW Classifying 3D Figures.