The Lesson

A shape can be reflected. When a shape is reflected, each point on the shape is reflected in a line of reflection.

How to Reflect a Shape

Reflecting a shape is easy.


Reflect the shape in the line of reflection.


Let us start by choosing a point on the shape and reflecting it. We will reflect point A.


Draw a line from point A to the line of reflection, such that it meets the line of reflection at 90°.Don't forget: We can also say that the lines meet at a right angle or are perpendicular to each other.


Measure the length of this line from the point to the line of reflection.


Measure out the length found in Step 2 in the same direction on the other side of the line of reflection.
Point A has been reflected in the line of reflection to find A', the corresponding point on the reflected shape.Repeat for points B and C:


With all the vertices (corners) of the shape reflected, the reflected shape can be drawn:

Lesson Slides

The slider below shows another real example of how to reflect a shape.

What Is a Reflection?

A reflection flips a shape so that it becomes a mirror image of itself. A reflection is a type of transformation.

Visualizing a Reflection

To visualize a reflection, think of the reflection you would see in a mirror or in water. The orginal shape is called the object, the reflected shape is called the image:

Properties of Reflections

  • Each point in the image (the reflection) is the same perpendicular distance from the line of reflection as the corresponding point in the object. Point A' is the reflection of point A. They are both 3 squares away from the line of reflection. Point B' is the reflection of point B. They are both 1 square away from the line of reflection.
  • The image is the same size as the object.
If you were to fold the diagram along the line of reflection, the reflection would fit exactly over the original shape.