Primary 3 maths · Geometry · About 10 minutes
Draw perpendicular and parallel lines
Extend the lines mentally and check the right-angle mark or equal spacing.
Start the interactive lesson →Open practice activity
What you will learn
- Draw perpendicular and parallel lines
Models used: number sentences, stories, diagrams.
Before you start
Look at the space between the lines
These horizontal lines stay the same distance apart. They are parallel.
These horizontal lines stay the same distance apart. They are parallel.
Turning the page changes orientation but not the relationship. Crossing alone does not guarantee perpendicular lines.
Two parallel lines These lines meet at a square corner. They are perpendicular.
Two perpendicular lines In a rectangle, opposite sides are parallel. Neighbouring sides meet at right angles.
Look for both relationships in a rectangle
What did the picture help us see?
In a rectangle, opposite sides are parallel. Neighbouring sides meet at right angles.
Worked example: A new example, together
Which relationship do the marked lines show?
Extend the lines mentally and check the right-angle mark or equal spacing.
Parallel lines remain a constant distance apart.
The lines remain the same distance apart. Check that the distance stays constant.
The lines remain the same distance apart. Which relationship do the marked lines show?
parallel
Check that the distance stays constant.
The lines remain the same distance apart. Extending the lines would not make them meet.
The lines remain the same distance apart. The relationship is parallel.
The lines remain the same distance apart. Check the result against the question we started with.
The perpendicular distance between the two lines is unchanged.
We found parallel. Parallel lines remain a constant distance apart.
The lines remain the same distance apart.
Common mistakes to discuss
- Only upright lines count. Parallel and perpendicular describe a relationship, not a direction. Two slanting lines can be perpendicular.
Check your understanding
- Draw perpendicular and parallel lines
- recognise or construct line relationships independent of orientation
- check the answer against the original quantities and units
Explain your reasoning to an adult, then try a fresh question in the interactive lesson. A result from one attempt is not proof of lasting mastery.
Try this lesson →Related Primary 3 lessons
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- Recognise perpendicular and parallel linesRecognise perpendicular and parallel lines · About 10 minutes