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Watch: How do you transform a shape?

This video explains how shapes can be transformed through translation, reflection or rotation.

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What is reflection?

Did you know

Reflection is a type of transformation. To reflect an object, you need a mirror line.

When a shape is reflected, its size does not change - the image just appears 'flipped'.

Every point on the shape is the same distance away on the other side of the mirror line.

Using squared paper can be very handy to help you reflect an object.

Did you know
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Example 1

Let's go through the steps to reflect a shape.

A triangle beside a mirror line

When you are reflecting a shape, you don鈥檛 need to reflect the whole shape at once.

Instead, reflect each vertex (corner) of the shape. Make sure that each vertex is the same distance away from the mirror line as the original shape.

The points of a triangle marked and reflected either side of a mirror line

When you have plotted the reflected vertices, you join the points together again.

A triangle reflected either side of a mirror line

There you have your reflected shape!

Sometimes you reflect shapes in a grid. The steps to reflect the shape are exactly the same, but the reflected shape will have new coordinates.

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Example 2

Let's take a look at another example:

A shape one a grid below a mirror line with points marked A, B, C and D

The letters represent the coordinates of the original shapes vertices.

A - (3, 1)

B - (5, 1)

C - (4, 4)

D - (6, 4)

Like before, reflect each vertex of the shape in the mirror line.

Remember to make sure that each vertex is the same amount of squares away from the mirror line as the original shape.

A shape with points reflect either side of a mirror line

Now you have plotted the new vertices, join them to create the reflected shape.

Shape reflected either side of the mirror line

Can you see how the reflected vertices now have new coordinates?

Let鈥檚 see what they are:

Original CoordinateReflected Coordinate
A(3, 1)(3, 9)
B(5, 1)(5, 9)
C(4, 4)(4, 6)
D(6, 4)(6, 6)
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Activities

Quiz

Test your knowledge of reflection with this quiz!

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Activity 2

Pencil

You will need a piece of paper (ideally squared or dotted), a pencil and maybe a mirror for this activity.

Investigate which capital letters look exactly the same in each quadrant when reflected through two mirror lines

In this investigation, you are going to explore which capital letters have exactly the same reflection when reflected across two mirror lines.

'A' has been done for you below. Can you find the others?

Pencil
Reflected capital A across 2 mirror lines in 4 quadrants
Top Tip

Top Tip: There are 4 letters to find!

Click for the answers.

Extension Challenge: Have a go at drawing your initials in one quadrant and then reflecting them across two different mirror lines into the other three quadrants.

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Play our fun maths game Guardians: Defenders of Mathematica. game

Use your times tables and more maths skills to defeat monsters and reclaim the Kingdom of Mathematica

Play our fun maths game Guardians: Defenders of Mathematica
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