When a shape, pattern or image has one half that is the reflection of the other half, it can be described as symmetrical.

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

A regular polygon has sides that are all equal and angles that are all equal.

Find lines of symmetry in 2D shapes

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

A mirror line is also called the line of __________.

They have all equal sides and all equal angles.

A square is a regular polygon. What is true for all polygons?

Match each shape shown to the number of lines of symmetry it has.

This shape is a regular hexagon. It has {{ }} lines of symmetry.

The number of lines of symmetry in a regular polygon is __________ the number of sides it has.

Match the number of lines of symmetry to the shapes.

A __________ is a quadrilateral with two pairs of adjacent sides that are equal in length.

This kite is also a square. It has {{ }} lines of symmetry.

Look at these rectangles. Which does not show a line of symmetry?

Which of these shapes has more than one line of symmetry?

Which shape has been incorrectly sorted? 

This lesson will soon be taken down.

Find lines of symmetry in 2D shapes

Lesson outcome