A transformation is a process that may change the size, orientation or position of a shape.

Enlargement is a transformation that causes a change of size.

A scale factor is the multiplier between similar shapes that describes how large one shape is compared to the other.

The centre of enlargement is the point from which a shape is enlarged.

The absolute value of a number is its distance from zero.

Describing a negative enlargement

Maths

In this unit, pupils enhanced their understanding of enlargement. In this future unit, pupils investigate the effect of an enlargement on the perimeter and area of a 2-D shape and the volume of a 3-D shape. 

In the prior unit, pupils learnt about the different types of transformations. In this unit, pupils' knowledge is extended as negative scale factors are considered as are multiple transformations.

Further transformations

An enlargement will produce an image that is {{}} to the object.

Shape A is enlarged to give shape B. Shape B is smaller than shape A. This means that the scale factor is __________.

Which of these show an enlargement with a negative scale factor?

Shape A is enlarged to give shape B. The scale factor of this enlargement is {{}}.

An enlargement scale factor $$2$$, centre $$(3, 2)$$

An enlargement scale factor $$\frac{1}{2}$$, centre $$(2, 3)$$

An enlargement scale factor $$-2$$, centre $$(2, 3)$$

An enlargement scale factor $$-\frac{1}{2}$$, centre $$(2, 3)$$

An enlargement scale factor $$\frac{1}{2}$$, centre $$(3, 2)$$

Shape A is enlarged to give shape B. Describe the transformation.

An enlargement scale factor $$2$$, centre $$(1, 2)$$

An enlargement scale factor $$\frac{1}{2}$$, centre $$(0, 2)$$

An enlargement scale factor $$-2$$, centre $$(0, 2)$$

An enlargement scale factor $$-2$$, centre $$(1, 2)$$

An enlargement scale factor $$-\frac{1}{2}$$, centre $$(1, 2)$$

Shape A is transformed to give shape B. Describe the transformation.

When the scale factor of an enlargement is negative, the image is a {{ }} of 180° of the object.

Which diagram shows an enlargement by a positive scale factor?

Sam enlarges a shape. The image is smaller than the object and the orientation is different. Which of these statements is correct?

Shape A is enlarged by the scale factor $$-\frac{1}{3}$$ to give shape B. The scale factor that would map shape B back onto shape A is {{}}.

Shape B is enlarged to give shape A. What is the scale factor of the enlargement?

Shape A is transformed to give shape A. Describe the transformation fully.

This lesson will soon be taken down.

Describing a negative enlargement

Lesson outcome