A shape has line symmetry if you can fold it along a line and the two halves match.
Flip the shape
Flip: in the y-axis
Each point (x, y) maps to (−x, y). Distances and angles stay the same — only the handedness flips.
original image
How many lines?
- Equilateral triangle: 3.
- Square: 4.
- Regular pentagon: 5.
- Circle: infinitely many.