Lines of Symmetry

Lines of Symmetry

A line of symmetry is a line that divides a figure into two matching halves. If you fold the shape along that line, the two sides should overlap exactly. In these exercises, the main task is to identify all such lines and give the final answer in its simplest form.

How to work it out

1. Look for matching halves. Check whether the left and right sides, or the top and bottom, mirror each other.
2. Test possible lines. A symmetry line may be vertical, horizontal, or slanted, depending on the figure.
3. Use key points. Compare vertices, edges, and curves. If each point on one side has a partner at the same distance on the other side, the line may be correct.
4. Count carefully. Some shapes have one line of symmetry, while others have several. Record only the lines that work.

Final check

Imagine folding the figure along each proposed line. If both halves coincide exactly, the line is correct. If even one part does not match, reject that line.

Helpful tip

When a shape has more than one line of symmetry, list them clearly and avoid duplicates. The final answer should be simplified and exact.