Scale Factor

What is Scale Factor?

When we enlarge or shrink an object, this is called a transformation. The amount of increase or decrease from one object to another is called the 'Scale Factor'[br]

EXAMPLE: By which scale factor have we enlarged the green rectangle to result in the blue rectangle?

Answer

This is enlarged by a scale factor of 3, as each of the shapes sides have been multiplied by 3.

Try It Yourself! Use the slider to see how a different scale factor can manipulate a transformation.

Question: By what scale factor was the green rectangle enlarged by to get the blue?

By what scale factor was the green rectangle enlarged by to get the blue?[br]

Centre of Enlargement

When completing the transformation yourself, the position is determined by a point called the center of enlargement.

For Example, here you can see the centre of enlargement is labelled 'A'

Try It Yourself

Use the slider on the image above to manipulate the scale factor, and note down what you notice about how it moves around the center of enlargement 'K'. [br]You should also be able to change the co-ordinates of 'A', see how this affects the transformation