A scale factor can be used to enlarge or reduce a shape. A missing length on a reduction/enlargement figure can be calculated by finding its linear scale factor.

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A **scale factor** can be used to enlarge or reduce a shape.

Shape A below is enlarged by scale factor to give Shape B.

The scale factor describes the **size** of an enlargement or reduction.

For example, a scale factor of means that the new shape is twice the size of the original.

A scale factor of means that the new shape is three times the size of the original.

A scale factor of means that the new shape is half the size of the original.

To calculate the scale factor, we use the following:

You can get the 'big' and 'small' from the corresponding sides on the figures.

- Question
Rectangles is an enlargement of rectangle . What is the length of ?

is on the bigger rectangle, therefore we will be using an

**enlargement**scale factor.Therefore is times .

So,

(You can type in your calculator )