standard_description: Prove the slope criteria for parallel and perpendicular lines and use them to solve geometric problems (e.g., find the equation of a line parallel or perpendicular to a given line that passes through a given point).
problem_activity: Narrative
The purpose of this activity is for students to learn stage 3 of the Geoblocks center. Students describe solid shapes using their own language. Students provide clues so that their partner can identify the shape out of a set of 4-6 solid shapes. While students may correctly name the solid shapes, it is not expected in this lesson. Students may describe the shapes in many ways. Monitor for students who:
reference a familiar object: “This shape looks like a ball.”
describe attributes or parts of the shape, such as point and circle for a cone.
use the name of the shape: “This shape is a cube.”
use positional words: “This shape is next to the one that looks like a box.”
The purpose of the activity synthesis is to highlight the language students use to describe shapes (MP6).
MLR8 Discussion Supports.
Synthesis: For each response that is shared, invite students to turn to a partner and restate what they heard, using descriptions and gestures.
Advances: Listening, Speaking
Action and Expression: Internalize Executive Functions.
Invite students to plan how they will describe the shape to their partner.
Supports accessibility for: Organization, Conceptual Processing
Required Materials
Materials to Gather
Geoblocks
Solid shapes
Required Preparation
Each group of 2 students needs 4–6 different solid shapes.
Launch
Groups of 2
Give each group of students 4–6 different solid shapes.
“We are going to learn a new way to do the Geoblocks center. It is called Geoblocks, Describe and Find.”
“Put the solid shapes in the middle, between you and your partner.”
30 seconds: partner work time
Activity
“Think of a shape but don’t tell your partner. Describe one of the shapes to your partner. Your partner’s job is to guess which shape you are describing. Once your partner figures out which shape you are describing, switch roles.”
7 minutes: partner work time
Monitor for students who describe the shapes in the ways described in the activity narrative.
Advancing Student Thinking
If students guess a shape that is not being described, consider asking:
“What clues did your partner give you?”
If needed, consider prompting students to eliminate some of the shapes. For example, ask “Your partner said that the shape has a round part. Are there any shapes that do not have round parts?”
Activity Synthesis
Invite previously identified students to share.
“Which clues did your partner give that were helpful to you?” (My partner said their shape was tall and had a circle on the top and bottom.)


aligns: no