Page 160 - MAT KS3 Y8 Cambridge CheckPoint

16 Position and movement

In earlier work you learned how to transform 2D shapes by Key words
reflecting, translating or rotating them.
Make sure you learn and
Here is a summary of the key points.
understand these key words:
The shape before any transformation is called the object.
transform
The shape after the transformation is the image. object

You need a mirror line to reflect a shape. image
mirror line reflect
translate
object image
y rotate
When you reflect a shape on a 3 x = 3 enlargement
coordinate grid, you can give the 2 co mbination of
equation of the mirror line. 1 transformations
0 scale factor
0 1 2 3 4 5 6 7 x
centre of enlargement
image

When you translate a shape you object
move it a given distance, right or
left and up or down. 2 squares up
3 squares left

centre of rotation
When you rotate a shape you turn it through a given object
number of degrees, or fraction of a whole turn. y image
3
You turn it about a fixed point, called the centre of rotation of 180° or 1
2 2
rotation. You turn it either clockwise or anticlockwise. turn
1
0
0 1 2 3 4 5 6 7 x

With any of these three transformations the shape only changes
its position. It doesn’t change its shape and size. An object and its
image are always identical. They are congruent.
An enlargement of a shape is a copy of the object, but it is bigger.

You can use a microscope to look at enlarged images of very small
objects. In this picture you can see a dust mite. These are about
0.04 mm long so they cannot usually be seen without the use of a
microscope. A typical mattress on a bed may have from 100 000 to
10 million mites inside it. This is not a very nice thought as you go to
bed at night!

In this unit you will look again at using reflections, translations and rotations to transform shapes. You
will also learn how to enlarge 2D shapes.

158 16 Position and movement