Identify lines of symmetry

🔶 What is a Line of Symmetry?

  • A line of symmetry is an imaginary line that divides a shape into two identical parts.
  • Both sides of the line are mirror images of each other.

🔶 Types of Symmetry:

  • Vertical Line of Symmetry – goes up and down (top to bottom).
  • Horizontal Line of Symmetry – goes side to side (left to right).
  • Diagonal Line of Symmetry – goes corner to corner.

🔶 Identifying Lines of Symmetry:

  • Fold the shape to see if the two halves match exactly.
  • If they match, the fold is a line of symmetry.
  • Some shapes have more than one line of symmetry.
  • Some shapes have no symmetry at all.

🔶 Examples:

ShapeLines of Symmetry
CircleInfinite
Square4
Rectangle2
Triangle (equilateral)3
Triangle (scalene)0
Heart1 (vertical)

🔶 Real-life Examples:

  • Butterflies
  • Leaves
  • Stars
  • Letters like A, M, T, U

Learn with an example

🎯 Is the dotted line a line of symmetry?

  • yes
  • no

Imagine folding this picture along the dotted line.

The two sides will match up exactly. The dotted line is a line of symmetry.

🎯 Is the dotted line a line of symmetry?

  • yes
  • no

Imagine folding this picture along the dotted line.

The two sides will match up exactly. The dotted line is a line of symmetry.

🎯 Is the dotted line a line of symmetry?

  • yes
  • no

Imagine folding this picture along the dotted line.

The two sides will match up exactly. The dotted line is a line of symmetry.

let’s practice!