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Grade 3 Math · World 9: Polygon Plaza · Level 83
Lines of Symmetry
Find all the lines of symmetry in a polygon.
Warm-up, learn, try it together, practice, then a quick check. About 15 minutes.
What children learn in Level 83
- A line of symmetry folds a shape into two halves that match exactly. This rectangle folds in half top to bottom.
- Your turn! Tap each dashed line to fold the rectangle there. Which folds match?
- The corner-to-corner fold doesn't match! A rectangle has just 2 lines of symmetry.
- A square has 4 lines of symmetry: up and down, side to side, and both corner to corner.
- Some shapes have none, like this parallelogram. No fold makes the halves match.
Georgia's K-12 Mathematics Standards:
- 3.GSR.6.3 — Identify lines of symmetry in polygons.