New
New
Year 7

# Describing a reflection

I can understand the minimum information required to describe a reflection

New
New
Year 7

# Describing a reflection

I can understand the minimum information required to describe a reflection

## Lesson details

### Key learning points

1. The image is a reflection of the object.
2. A line of reflection can be thought of as a mirror line.
3. The line of reflection can be vertical.
4. The line of reflection can be horizontal.
5. The line of reflection can be diagonal.

### Common misconception

Line segments connecting corresponding points on an image and object can intersect each other.

Corresponding point line segments after a reflection never intersect. If they do, then corresponding points have not been paired correctly.

### Keywords

• Line of reflection - The line of reflection is the line about which an object is reflected. The object and image are equidistant from the line of reflection.

• Equidistant - Points A and B are equidistant from a third point C if the distance AC is equal to the distance BC.

Lines of reflection will be more succinctly described in the future when they cover topics involving equations of horizontal and vertical lines - for now, defining the line of reflection using two coordinates is effective at keeping the lines unique.
Teacher tip

### Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

## Starter quiz

### 6 Questions

Q1.
Which of these sentences use the word "sense" correctly?
Correct answer: The sense of a word stays the same after a rotation because I can still read it
The sense of a word changes when I enlarge it because the letters get bigger
The sense of a word stays the same after reflection as I can read it in a mirror
Correct answer: The sense of a word changes if the letters are rewritten backwards
Q2.
In which of these images has the sense changed compared to the object?
image 2
image 4
image 5
Q3.
Write down a transformation that changes the "sense" of an object.
Q4.
When an object is reflected, the size of its angles are invariant. This means the angles remain .
Correct Answer: the same, same, exactly the same, unchanged, invariant
Q5.
Complete this sentence: "When an object is reflected, the orientation of the object _______ ."
is invariant
sometimes changes
Q6.
Which of these diagrams shows a reflection?
Correct Answer: An image in a quiz

## Exit quiz

### 6 Questions

Q1.
What is the purpose of a "line of reflection"?
It cuts the object in half to become an image.
It is in the middle of a shape.
Correct answer: It defines the position of the reflected image.
It defines the size of the reflected image.
It defines the rotation of the reflected image.
Q2.
What does the word "equidistant" mean?
Correct answer: Two or more things that are an equal distance away from a reference point.
When two points on an object are a distance away from the image.
When two corresponding points are parallel to the \$\$x\$\$-axis or \$\$y\$\$-axis.
Correct answer: When two corresponding points are an equal distance from the line of reflection.
Q3.
Which pieces of information are needed to fully describe a reflection?
Correct answer: state that it's a reflection
show the orientation of each of its vertices
describe how its sense will change
Correct answer: state if it's a horizontal, vertical, or diagonal reflection
Correct answer: describe the location of the line of reflection
Q4.
Which of these coordinates are suitable for defining the location of the line of reflection for this reflection?
(0, 9)
(6, 3)