Transformations and Enlargements

Transformations and Enlargements

1. Translation - moving an object up or down, or from side to side. NOT changing the objects shape, size or direction.

   • Using vectors to describe translations - top number is how much it has been moved side to side, bottom number is how much it has been moved up or down.
     • A move downwards or left is indicated by a - sign.

2. Reflections - When an object is transformed by a reflection the object and its image are always the same perpendicular distance from the mirror line. Perpendicular means 'at right angles to'.

3. Enlargements - when an objects size changes.

   • When working out enlargements, you will need to know the scale factor and centre of enlargement. The scale factor tells us by how much the object has been enlarged. The centre of enlargement tells us where the enlargement is being measured from.
     • Fractional scale factors; If we 'enlarge' a shape by a scale factor that is between -1 and 1, the image will be smaller than the object
     • Negative scale factors - An enlargement using a negative scale factor is similar to an enlargement using a positive scale factor, but this time the image is on the other side of the centre of enlargement, and it is upside down. (Multiply all coordinates by -n).