Shapes can be transformed in ways such as translation, rotation, reflection and enlargement. Enlargement is described by its scale factor and the position is described by the centre of enlargement.

Part of

The **position** of the enlarged shape is described by the
**centre of enlargement** (O in the following diagrams).

To enlarge the triangle with a scale factor of and centre of enlargement O, take the following steps:

For a scale factor of :

OA' = Ć OA

OB' = Ć OB

OC' = Ć OC

For a scale factor of :

OA' = Ć OA

OB' = Ć OB

OC' = Ć OC

Sometimes the centre of enlargement lies on or within the original shape. Look at the following examples:

- Question
What are the scale factors of enlargement for shapes A and B?

A)

B)