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Plane shapes

The systems used for naming and classifying plane shapes are simple and logical, although some students find them complex.

In particular, when the definitions of quadrilaterals are considered inclusive, the concept can be quite challenging for students to understand. You can find a comprehensive list of quadrilateral definitions and properties on the BBC Bitesize website.

The naming and classification systems can be made meaningful to students through activities such as making models and mobiles or creating Venn and tree diagrams. These classroom activities build bridges from the informal interpretations encountered in the early years through to more formal approaches.


There are several different ways to classify simple polygons, using the number of sides, the length of sides, the sizes of angles and other properties.

Curriculum links

Foundation: Sort, describe and name familiar two dimensional shapes and three dimensional objects in the environment

Year 1: Recognise and classify familiar two dimensional shapes and three dimensional objects using obvious features

Year 5: Describe translations, reflections and rotations of two dimensional shapes. Identify line and rotational symmetries

Year 7: Classify triangles according to their side and angle properties and describe quadrilaterals

Year 8: Establish properties of quadrilaterals using congruent triangles and angle properties, and solve related numerical problems using reasoning