Grade 5 · Unit 8: Location and transformation

Symmetry

Line and rotational symmetry together.

Symmetry in architecture

Architects use symmetry for balance and beauty. Many buildings have a line of symmetry down the middle. Domes and windows often have rotational symmetry.

Both kinds

This star has 5 lines of symmetry. It also has rotational symmetry of order 5. Regular polygons have both.

Comparing shapes

A parallelogram has no lines of symmetry but order 2. A kite has 1 line but order 1 (no rotational symmetry). Check each separately.

Designing with symmetry

Start with a quarter of a design. Reflect it twice for 2 lines of symmetry. Or rotate it for rotational symmetry.

Tessellations

Shapes tessellate when their angles fit around a point to make 360°. Six triangles (6 × 60°), four squares (4 × 90°) or three hexagons (3 × 120°) meet at a point. A regular pentagon (108°) cannot: 3 × 108° = 324°, leaving a gap.

What I learnt

• I can find lines of symmetry and the order of rotational symmetry.
• I can design symmetrical patterns.