Lines of Symmetry
A line of symmetry divides a shape into two matching mirror-image halves. Imagine folding the shape along the line: if both halves fit exactly on top of each other, it is a line of symmetry. Count every different line that works.
Common mistake: Do not count a line just because it passes through the middle of a shape. The two sides must be matching mirror images, so a parallelogram usually has no lines of symmetry.
Worked example:
How many lines of symmetry does the shape have?
- A non-square rectangle has a vertical line of symmetry and a horizontal line of symmetry.
Answer:
A rectangle has 2 lines of symmetry.