Line and Rotational Symmetry
Recognise line and rotational symmetry of shapes and create symmetrical patterns and pictures.
Read this first
A shape has line symmetry if it folds onto itself.
Fold this down the middle. Both halves match.
Words you need
- Line of symmetry
- A fold line where both halves match.
- Rotate
- Turn a shape around a point.
- Symmetrical
- The same on both sides.
Worked example
e.g. How many lines of symmetry has a square?
- Try folding it down the middle. The halves match. That is one line.
- Try folding it across the middle. They match too. That is two.
- Now try the two corner folds. They match too.
- A square has 4 lines of symmetry.
Test every fold. Do not stop at the first.
Practice
The pictures fade as you go. By the last few you are on your own.
1Does this pattern have a line of symmetry?with a picture
AnswerYes. Fold it down the middle.
2How many lines of symmetry has a rectangle?with a picture
AnswerTwo. One across and one down.
3How many lines of symmetry has a circle?with a hint
Need a hint?
Try folding it any way at all.
AnswerToo many to count. Every fold through the middle works.
4Has the letter H got a line of symmetry?with a hint
Need a hint?
Try folding it two ways.
AnswerYes, two. Across and down.
5Has the letter R got a line of symmetry?on your own
AnswerNo. It does not fold onto itself.
6How many lines of symmetry has an equilateral triangle?on your own
AnswerThree.
7Turn a square a quarter turn. Does it look the same?on your own
AnswerYes. That is rotational symmetry.
Think about it
1
What is the difference between folding and turning?
One good answerFolding is line symmetry. Turning is rotational symmetry.
2
Can a shape have turning symmetry but no fold line?
One good answerYes. A pinwheel does.
Common mistakes
Guessing without folding.
Test it. Trace the shape and fold the paper.
Thinking every shape is symmetrical.
Many are not. The letter R has no fold line.