01 Key Concepts
Line Symmetry (Reflectional Symmetry)
A shape has line symmetry if it can be folded along a line so that both halves match perfectly; that fold line is called the line of symmetry.
Number of Lines of Symmetry
Different shapes have different numbers: a square has 4, an equilateral triangle has 3, a circle has infinitely many.
Rotational Symmetry
A shape has rotational symmetry if it looks the same after being rotated less than a full 360° turn around its center.
Order of Rotational Symmetry
The number of times a shape matches itself during one full 360° rotation.
Point Symmetry
A special case of rotational symmetry where a shape looks the same after being rotated exactly 180°.
02 Solved Examples
Example 1 How many lines of symmetry does a square have?
- A square can be folded along 2 diagonals and 2 lines through the midpoints of opposite sides.
- That totals 4 distinct lines.
Answer: 4 lines of symmetry
Example 2 Does the letter 'H' have line symmetry?
- Check if a vertical line down the middle creates matching halves: yes.
- Check if a horizontal line through the middle also creates matching halves: yes.
Answer: Yes, it has both a vertical and a horizontal line of symmetry
Example 3 Find the order of rotational symmetry for an equilateral triangle.
- An equilateral triangle matches itself after rotating 120°, 240°, and 360°.
- That's 3 matches within one full rotation.
Answer: Order 3
03 Practice Questions
1How many lines of symmetry does an equilateral triangle have?
3
2How many lines of symmetry does a regular pentagon have?
5
3Does the letter 'A' typically have a line of symmetry?
Yes, a vertical one
4Find the order of rotational symmetry for a square.
4
5How many lines of symmetry does a circle have?
Infinitely many
📄 Symmetry — Downloadable Worksheet
10 questions with a full answer key. Grab the PDF to print, or try the interactive version in your browser.