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Classifying Quadrilaterals by Parallel Lines
Students will be able to classify quadrilaterals with parallel lines using a Venn diagram.
- Display three different paper cutouts to your students: a rectangle, a rhombus, and a trapezoid. Ask students to turn to a neighbor and explain how the shapes are alike and different.
- Call your class to attention and have students share out something they either overheard or observed. After each share, ask students to give a thumbs up if they agree, thumbs to the side if they aren't sure, or thumbs down if they disagree.
- Announce each answer as true or false, (with explanations) after students have shown their thumb signals.
- Explain to your class that we use detailed observations, called traits, to describe things. Tell students they can classify, or put, somethig in a category by it's traits.
Explicit Instruction/Teacher modeling(10 minutes)
- Draw a two-ring Venn diagram, with the following categories: parallelogram (a figure with two pair of opposite lines with an equal distance between them), and quadirlateral (a four-sided figure). Explain to your students that we call opposite lines that have an equal distance between them, parallel lines.
- Note that where the Venn diagram rings overlap, is where you would classify a shape with both traits: having 4 sides and a pair of parallel lines.
- Show your class the paper cutout trapezoid. Explain that you will use the Venn diagram to classify the shape based on traits of having 4 sides and/or having a pair of parallel lines.
- Point out to your students how the trapezoid can be classified as a quadrilateral. However, it can't be classified as a parallelogram becuase both pair of lines are not parallel.
- Write 'trapezoid' in the quadrilateral section of the Venn diagram.
Guided Practice(5 minutes)
- Explain that you will now select a student to role-play as the teacher.
- Choose a student to present a shape to the class. Explain that they will use the Venn diagram to classify the shape based on traits of having 4 sides and/or having a pair of parallel lines.
- Have the student call out the name of the shape and ask the class 3 questions. Can the shape can be classified as:
- a quadrilateral?
- a parallelogram?
- or as both ?
- Students can respond silently by a show of thumbs, (as in the lesson's introduction.) Finally, have the student-as-teacher note the name of the shape in the corrrect section of the Venn diagram.
Independent working time(15 minutes)
- Answer any clarifying questions before releasing students to complete the Categorizing Quadrilaterals worksheet.
Enrichment: Challenge students to create a three-ring Venn diagram and introduce new shapes.
Support: Create a word bank with definitions on sentence strips. * Provide sentene frames for students to use when giving explanations.
- Circulate during work times and ask students to explain their choices.
Review and closing(10 minutes)
- Review the Categorizing Quadrilaterals worksheet as a class and have students defend each shape’s placement on their diagram.