Axial Symmetry

Axial symmetry is when a figure has a special line and both sides of the line are mirror images of each other. If you fold the figure along this line, the two halves match exactly. This line is called the axis of symmetry.

In the picture below, the two triangles are mirror images of each other. The vertical line is the axis of symmetry.

Let’s draw the mirror image of a triangle on graph paper.

1. Draw the mirror vertices: For each vertex of the triangle, count how many squares it is from the axis of symmetry (to the left or to the right). Place a new point on the other side of the line, the same number of squares away.
2. Draw the mirror figure: Connect the mirror vertices with straight lines in the same order as the original triangle.