Lines of Symmetry in 2D Geometric Shapes
Print 4th grade geometry worksheets identifying lines of symmetry in 2D shapes, testing lines of reflection, and counting symmetry lines with answer keys. Aligned with Common Core standard CCSS 4.G.A.3.
Worksheet version 1 of 12. Generates reproducible symmetry problems with an exact matching answer key.
1. Is the dashed line a line of symmetry for this isosceles triangle?
Line of symmetry? [ Yes / No ]
2. Is the dashed diagonal line a line of symmetry for this rectangle?
Line of symmetry? [ Yes / No ]
3. How many lines of symmetry does a square have?
Lines of symmetry: ________
4. How many lines of symmetry does a general parallelogram have?
Lines of symmetry: ________
5. The left half of a symmetrical heart is shown on the grid. Complete the right half.
Draw the missing half on the grid.
6. How many lines of symmetry does the capital letter 'A' have?
Lines of symmetry: ________
Understanding Lines of Symmetry
A line of symmetry divides a shape into two identical mirror-image halves. When the shape is folded across the line of symmetry, both halves match up point-for-point.
- Equilateral triangle: 3 lines of symmetry.
- Square: 4 lines of symmetry (horizontal, vertical, 2 diagonals).
- Rectangle (non-square): 2 lines of symmetry (horizontal, vertical). Note: Diagonals are not lines of symmetry for non-square rectangles!
- General parallelogram: 0 lines of reflectional symmetry.
- Regular n-gon: Has exactly n lines of symmetry.
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