Page 163 - Cambridge Checkpoint Mathematics Coursebook 7_Slide 02

17 Position and movement
xx xxx

A transformation happens when you move a shape by refl ecting, Key words
translating or rotating it.

Th e shape you start with is called the object. Th e shape you fi nish Make sure you learn and
understand these key words:
with, aft er a transformation, is called the image.
You see transformations in everyday life. transformation
refl ect
Look in a lake, a river or the sea on a calm day and you will see a translate
refl ection. In the picture below you can see the mountains, clouds, rotate
jetty, trees and stone wall all refl ected in the lake. object
image
refl ection
translation
rotation
congruent
mirror line
line of symmetry
centre of rotation
clockwise
anticlockwise

In the picture on the right you can see someone fi ring an arrow
in an archery competition. When the arrow hits the target it will
have undergone a translation from where it started to where it
fi nished.
In the bottom picture you can see the Singapore Flyer. It is one
of the largest Ferris wheels in the world. It is 165 metres tall, has
28 capsules and can carry a maximum of 784 people at a time.

Th e wheel turns or rotates about its centre. Each complete rotation
takes about 32 minutes.

When a shape undergoes a transformation it only changes its
position. It doesn’t change its shape and size. An object and its
image are always identical or congruent.
In this unit you will learn more about transformations of plane
shapes.

17 Position and movement 161