If you were to fold a shape on its line of symmetry, both halves would match exactly.

Mirror line is another term to describe the line of symmetry.

When you reflect a shape, you flip it over a mirror line or line of symmetry without turning it or changing the size.

The reflection of a shape is the mirror image of a shape.

Reflect polygons that are dissected by the line of symmetry

Maths

In this unit pupils will pupils will complete and compose symmetrical shapes from two congruent shapes and investigate lines of symmetry in 2D shapes. In the future unit pupils will explain what area is and measure using counting as a strategy. They will make different shapes with the same area and compare the area of different shapes. 

In the prior unit pupils investigated ways to compose and decompose polygons. They investigated quadrilaterals with and without parallel and perpendicular sides. In this unit pupils will complete and compose symmetrical shapes from two congruent shapes and investigate lines of symmetry in 2D shapes.

Properties of 2D and 3D shapes and symmetry

 This shape has been reflected. Each vertex is __________  from the line of symmetry.

Which of these images shows a correct reflection?

Which of these images is not a correct reflection?

Here are are three different triangles that have been reflected in the line of symmetry. Name the new shapes that have been made.

True or false. When you reflect a rectangle that has a side that touches the mirror line, it will create a larger rectangle.

The reflection of a shape is sometimes called a __________.

True or false. This image shows a reflection.

Sam is using vertices to reflect this shape. Which vertex is in the wrong position on the grid?

the shape is not the same distance from the mirror line.

the shape has not been flipped over the mirror line.

Complete the sentence. This image does not show a reflection because __________

This lesson will soon be taken down.

Reflect polygons that are dissected by the line of symmetry

Lesson outcome