A line of symmetry is a line that divides a figure into two parts that are mirror images of each other.
Each half must look exactly the same but flipped, like a reflection in a mirror.
To identify a line of symmetry, imagine folding the shape along a line. If the two halves match perfectly, the line is a line of symmetry.
Not every line drawn through a shape is a line of symmetry—only the ones where both sides match exactly.
Many familiar shapes have predictable numbers of lines of symmetry. Knowing these can help you recognize symmetry quickly.
Shapes may have zero, one, or many lines of symmetry. Be sure to test carefully.
Symmetry is not only in math—it appears in nature, art, and design. Recognizing symmetry can help you understand patterns and balance.
When you see symmetry in the real world, think of it as nature or design using the same rule you use in geometry.