Fold a sheet in half, cut out a design on the fold and open it: the two halves are equal, one “reflecting” the other. This figure has symmetry.

The axis of symmetry

DefiniçãoAxis of symmetry

A figure has axis of symmetry when there is a line that divides it into two halves that meet fit perfectly when folding the figure along this line. Each half is the reflection of the other in a mirror.

Click on the squares on one side: the mirror paints the other. Try the butterfly and change the axle.

How many axes does a figure have?

  • The heart drawn has 1 axis (vertical).
  • The rectangle has 2 axes: one standing and one lying down.
  • The square has 4 axes: two through the middle of the sides and two through the diagonals.
  • The circle has infinite axes: any line that passes through the center.
  • Some figures have no axis at all, like the letter F.
The four axes of symmetry of the square.
Check the answer

A (vertical), B e C (horizontal), H e X (vertical and horizontal). F e R have no axis of symmetry.

True or false?

  1. The square has 4 axes of symmetry.
  2. The rectangle that is not square has axes on the diagonals.
  3. The circle has infinite axes of symmetry.
  4. The letter F has an axis of symmetry.