The big idea
Two halves that match
A shape is SYMMETRIC if you can draw a line through it and the two sides become mirror images. Fold the shape on that line and the halves stack perfectly on top of each other.
Symmetry is everywhere — butterflies, your face, hearts, letters like A and M and W. Builders, painters, and designers use it because it looks balanced. Brains love balance.
Some shapes have one line of symmetry. Some have many (a circle has infinite!). Some have none at all.
- A line of symmetry splits a shape into two MIRRORED halves.
- Fold along the line — halves match exactly.
- A shape can have 0, 1, 2, or even infinite lines of symmetry.