Jumping Into Geometry!
Students will be able to define and identify three types of polygons.
- Tell students that today they will be learning about different types of polygons.
- Pass out lined paper to students.
- Explain that polygon is just a fancy word meaning a shape with three or more straight sides and angles, you may want to review the definition of "angle".
- Write the word "polygon" and its definition on the board, and have students copy this on their paper.
- Create a t-chart on the board underneath the definition. On one side write "examples." On the other side write "non-examples." Students should recreate this on their paper.
- Draw a picture of a square on the "examples" side. Explain that this is a polygon because it is a closed shape with four sides and four angles.
- Draw a picture of a circle on the "non-examples" side. Explain that although it is a closed shape, this is not a polygon because it does not have straight sides or angles.
- Draw a picture of a shape that is not closed on the "non-examples" side. Explain that although it has angles and straight sides, this is not a polygon because it is not closed.
- Give students a few minutes to work with a partner and continue drawing examples and non-examples of polygons.
- Have some students come to the board to share their examples and non-examples.
Explicit Instruction/Teacher modeling(10 minutes)
- Explain that there are many different types of polygons. Tell students that they will focus on three kinds today: triangles, quadrilaterals, and pentagons.
- Draw a three-columned chart on the board with the titles "triangle," "quadrilateral," and "pentagon." Have students copy this on their paper.
- Acknowledge that many students know what a triangle is. Draw a triangle on the board and have students copy it.
- Circle the root word "tri" in the word "triangle" and have students do the same. Ask students what other words start with "tri"? Possible answers include tricycle, triplets, tripod, and triathlon.
- Write these in the "triangle" column and have students do the same. Ask students what they think "tri" means.
- See if students can come up with "three." Point out how each of the examples has something to do with the number three.
- Repeat the process for quadrilateral and pentagon. Make sure to clarify the meaning of any new words with students.
Guided Practice(15 minutes)
- Tell students that they will now begin a scavenger hunt for triangles, quadrilaterals, and pentagons around the classroom.
- Model for students how to do this by finding an object around the classroom for each of these polygons. Write the objects under the appropriate heading of your chart.
- Allow students to work in partners and move around the classroom, looking for examples of these polygons and writing them down.
- After several minutes, have students return to their seats and share some of the examples they found. Have students add to their chart as they hear new examples.
Independent working time(10 minutes)
- Have students put away their lined piece of paper.
- Hand out Which Shapes are Polygons?
- Have students complete the worksheet as the directions indicate. Additionally, have students label all triangles with a "T," all quadrilaterals with a "Q," and all pentagons with a "P."
- Review worksheet with students when they are finished.
- Enrichment: Give students the terms "octagon" and "decagon" with the root words "oct" and "deca" circled. Have these students generate more words with these root words, like octopus and decade, and challenge them to determine the meaning of the root words. Then have these students come up with a definition for "octagon" and "decagon."
- Support: Students who are struggling during independent time may use their notes to help them as they work.
- Hand out a note card to each student.
- Have students write the definitions of triangle, quadrilateral, and pentagon, as well as draw a picture of each.
Review and closing(5 minutes)
- Say each prefix out loud and have students show you the number it represents with their fingers.
- Challenge students to continue looking for words with these prefixes as they read.
- Have students turn and talk with the person next to them about what makes a polygon a polygon, and review this definition as a class.