Lesson 5

Trapezoids

Lesson Purpose

The purpose of this lesson is for students to explore two different definitions of trapezoid.

Lesson Narrative

The purpose of this lesson is for students to explore trapezoids and agree on a definition of trapezoids for this course. In the first activity, students see two different definitions for a trapezoid both of which are commonly used, one that excludes parallelograms and one that includes parallelograms. The exclusive definition of a trapezoid states that a trapezoid has exactly one pair of opposite sides that are parallel. The inclusive definition states that a trapezoid has at least one pair of opposite sides that are parallel. In the second activity, students recognize that we have chosen to use the inclusive definition of a trapezoid. Students should have access to straight edges, protractors, and patty paper throughout this lesson.
  • Engagement
  • MLR8

Activity 1: What’s a Trapezoid?

Learning Goals

Teacher Facing

  • Compare different definitions for trapezoids, and use them to identify trapezoids.

Student Facing

  • Let’s explore trapezoids.

Required Preparation

CCSS Standards

Addressing

Building Towards

Lesson Timeline

Warm-up 10 min
Activity 1 20 min
Activity 2 15 min
Lesson Synthesis 10 min
Cool-down 5 min

Teacher Reflection Questions

Did students notice the difference in the definitions of the trapezoid? How did they explain that difference in terms of the hierarchy on the anchor chart?

Suggested Centers

  • Can You Draw It? (1–5), Stage 6: Shapes on the Coordinate Grid (Addressing)
  • Which One? (K–5), Stage 6: Shapes on the Coordinate Grid (Addressing)
  • How Are They the Same? (1–5), Stage 4: Grade 4 Shapes (Supporting)

Print Formatted Materials

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Additional Resources

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