Horizontal and vertical
The horizon is horizontal. A lamp post is vertical.
across
up and down
Use direction words first.
Year 3
Identify horizontal and vertical lines and pairs of perpendicular and parallel lines
Recognise line directions and identify when lines are parallel or perpendicular.
Lesson overview
Geometry - properties of shape
Horizontal lines go across. Vertical lines go up and down. Parallel lines stay the same distance apart and never meet. Perpendicular lines cross to make right angles.
Parallel lines
Railway tracks look like parallel lines because they stay the same distance apart.
never meet
crossing lines
Parallel lines do not cross.
Perpendicular lines
A horizontal line and a vertical line can meet to make a right angle.
forms a right angle
benchmark
Perpendicular lines cross and make right angles.
Worked example
A window frame has two vertical sides and two horizontal sides. Which pairs are parallel?
parallel pair
parallel pair
- Look for lines going in the same direction.
- The two vertical sides stay the same distance apart, so they are parallel.
- The two horizontal sides also stay the same distance apart, so they are parallel.
- Where a vertical and horizontal side meet, they are perpendicular.
Try it
Name the line direction first, then decide whether the lines stay apart or meet at a right angle.
Question 1
Which word describes a line that goes across?
across
up and down
Question 2
Parallel lines...
same distance apart
meet at right angles
Question 3
Perpendicular lines make...
Question 4
How many horizontal sides does a rectangle have?
2 horizontal2 vertical
Question 5
Which statement is correct?
Common mistakes
Watch for these when working through the lesson.
- Calling any crossing lines perpendicular.
- Mixing up horizontal and vertical.
- Thinking parallel lines must be vertical.
Related topics
These ideas fit closely with this lesson.
- Identify whether angles are greater than or less than a right angle.
- Draw 2-D shapes and make 3-D shapes using modelling materials.