1. http://www.youtube.com/watch?v=v0XUqliEnPQ

3. First, learn how to move shapes around a grid using reflections.

4. For a reflection you always need to know where the mirror line (or line of symmetry) is. Mirror line

5. Y= 0 X= 0 Here are the second most important lines you also need to know.

6. Reflect shape ‘A’ into line X=1 Now reflect shape B into line X=1

7. - If the scale factor is bigger than 1 then the shape gets bigger. (NOT TO SCALE) A to B is an enlargement, Scale factor 1 1/2 If the scale factor is smaller than 1 (i.e. a fraction like ½), then the shape gets smaller.

8. A B A to B is an Enlargement of scale factor ½ (Really this is a reduction, but you still call it an enlargement, scale factor ½ (NOT TO SCALE)

9. A’ B’ 5.5 cm 16.5cm 12 cm 4 cm C’ 9 cm A B DC 3 cm D’ The Centre of Enlargement The scale factor also tells you the relative distance of old points and new points from the centre of enlargement. This is very useful for drawing an enlargement, because you can use it to trace out the positions of the new points from the centre of enlargement, as shown in the diagram.

10. The lengths of the two shapes (big and small), are related to the scale factor by this very important formulae triangle which you must learn: New length Scale factor x Old length

11. This now lets you tackle the classic “enlarged photo”, exam question with no difficulty. PHOTO 9cm 6.4 cm X cm ENLARGED PHOTO 11.25 cm To find the width of the enlarged photograph we use the formulae triangle twice, firstly to find the scale factor then to find the missing side: 1) Scale factor = new lengthOld length = 11.25 9 = 1.25 2) New width = scale factor x old width = 1.25 x 6.4 = 8cm