1. Symmetry Mirror lines 1.Line symmetry 2.Rotational symmetry Order of symmetry Line symmetry When an object is folded each half reflects on itself. Each refection line is called an Axis of symmetry. A square reflects in its diagonals (blue lines) and also in the yellow lines. A rectangle only has two lines of symmetry. It will not reflect in its diagonals. Try folding an A4 piece of paper along its diagonals and you will clearly see this. Activity: Fold a piece of paper, coloured or white, and cut out shapes along the fold line. If you have difficulty with this see Starter Page 281.

2. Symmetry Mirror lines 1.Line symmetry 2.Rotational symmetry Order of symmetry Rotational symmetry When an object is rotated about O each corner maps onto the next corner. 1 moves to 2, 2 moves to 3, 3 moves to 4 and 4 moves to 1. It has a rotational order of 4. A rectangle only has order of two symmetry. 1 moves to 3 and 2 moves to 4 Activity: Fold a piece of paper, coloured or white, and cut out shapes along the fold line. If you have difficulty with this see Starter Page 281. 1 3 2 O 4 1 23 O Ex 18.1 Page 279 Numbers 2, 3, 5, 6 Ex 18.2 Page 281-282 Numbers 1, 2, 3 7, 9

3. Total Order Of Symmetry 1 4 3 2 O Total order is the Line Symmetry Plus Rotational Symmetry. Total order for a square is 8 Line = 4 Rotational = 4 Total= 8 4 1 23 O Total order for a rectangle is 4 Line = 2 Rotational = 2 Total= 4

4. Total Order Of Symmetry Total order is the Line Symmetry Plus Rotational Symmetry. Total order for a square is 8 Line = 0 Rotational = 1 Total= 1 Total order 4 Line = 1 Rotational = 1 Total= 2 Ex 19.3 Numbers 1, 4, 5