Teaching parallel and perpendicular lines

Teaching Parallel and Perpendicular Lines

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Once fourth-grade students are confident in their knowledge of the undefined terms of geometry, including planes, points, and lines, you can move on to teaching parallel and perpendicular lines.

Math teachers can use different strategies to make these early geometry lessons fun, and today we’ll share a few such awesome strategies that will help you achieve this! Use these cool strategies and you’ll have students drawing parallel and perpendicular lines in no time!

Strategies for Teaching Parallel and Perpendicular Lines

A person drawing a line

Bell-Work

In earlier lessons, students have learned how to draw and identify points, lines, planes, line segments, and rays, as well as angles, including right, acute, and obtuse angles. To understand parallel and perpendicular lines, students need to understand these earlier terms.

So a good place to start when teaching parallel and perpendicular lines is a quick review of earlier lessons on the undefined terms of geometry and angles. For instance, you can draw a few such terms on the whiteboard, and ask students to identify them.

If you notice that there are students who are still struggling with this, you can use this video to review these geometry terms. In addition, you can refer to this article where you’ll find more tips and activities focused on the undefined terms of geometry.

What Are Parallel Lines?

After the brief bell-work, you can proceed by explaining what parallel lines are. You can define parallel lines as two lines that will never intersect or cross each other. Point out that parallel lines always stay the same distance apart.

Illustrate parallel lines by drawing an example on the whiteboard.

Two parallel lines

Then, draw several lines, some of which are parallel and some of which aren’t. Ask students to identify which lines are parallel by relying on what they’ve learned so far on parallel lines. How many pairs of parallel lines did they identify? The drawing can look like this:

A rectangle with various lines

Perpendicular Lines

Explain that perpendicular lines are two lines that intersect each other. They form right angles when they cross each other. Draw an example of perpendicular lines on the whiteboard, for instance:

perpendicular lines

Then, draw several lines, some of which are perpendicular and others aren’t. Ask students to identify which lines are perpendicular by relying on what they’ve learned so far on perpendicular lines. How many pairs of perpendicular lines did they identify? The drawing can look like this:

A rectangle with parallel and perpendicular lines

Additional Resources

You can also enrich your lesson with multimedia materials, such as videos. For instance, this video by Khan Academy is a good resource with step-by-step instructions and illustrations on parallel and perpendicular lines.

In addition, this video teaches students about parallel and perpendicular lines through a song. It also contains excellent illustrative examples. Let students learn this awesome song and sing together to practice the definitions of parallel and perpendicular lines!

Activities to Practice Parallel and Perpendicular Lines

Online Activity on Identifying Lines

This is an online activity that will help children sharpen their skills at recognizing and identifying parallel and perpendicular lines. Use this activity at the end of your lesson and make sure you have a sufficient number of technical devices for students.

The activity consists of several fun images where students need to identify whether two or more lines are parallel or perpendicular. For example, determining which stripes are parallel or perpendicular in the flag of Trinidad and Tobago.

Students perform this activity individually. In the end, you can go in rounds and reflect on the activity. Was it more difficult to identify parallel and perpendicular lines in real-world examples, such as flags? Was identifying parallel or perpendicular lines more challenging?

Online Activity on Drawing Lines

In this online activity, students will get to practice drawing parallel and perpendicular lines. Again, the only material needed to use this activity in your classroom is a suitable technical device for each student.

This is an individual activity. It contains several math questions where children are asked to draw either parallel or perpendicular lines. If they get stuck, they can also use a hint or watch a video for help. In the end, give your students the opportunity to briefly discuss the activity together.

Group Work

This is a group activity that will help students practice identifying parallel and perpendicular lines. To use this activity in your classroom, you just need to print out enough copies of this Interactive Notebook Worksheet (Members Only).

Divide students into groups of 3 or 4 and hand out the copies. Provide instructions for the game. The worksheet contains exercises with streets of different colors (purple, blue, pink green), that are either parallel or perpendicular.

Explain that the members of a group are supposed to work together in order to identify which pairs of streets are parallel and which ones are perpendicular. This is a fast-paced game, so the group that managed to answer the questions correctly is the winner of the game.

Before You Leave…

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This article is based on:

Unit 7 – Geometry