Exterior angles of polygons
I can find the sum of the exterior angles of a polygon.
Exterior angles of polygons
I can find the sum of the exterior angles of a polygon.
These resources will be removed by end of Summer Term 2025.
Lesson details
Key learning points
- The sum of the exterior angles of a polygon can be demonstrated using a point.
- The sum of the exterior angles of a polygon can be proven using interior angles and the angles on a straight line.
- The angle sum of a triangle can also be proven using exterior angles .
- The size of the exterior angle of any polygon can be found using the sum of angles.
Keywords
Interior angle - an angle formed inside a polygon by two of its edges.
Exterior angle - an angle on the outside of a polygon between an extension of an edge and its adjacent edge.
Supplementary angle - a pair of angles that sum to 180°.
Common misconception
The exterior angle is the entire reflex angle that is on the outside of each vertex of a shape.
Ask a pupil to stand and walk around the room to trace a shape. The angle that the pupil turns at each vertex is an exterior angle.
To help you plan your year 8 maths lesson on: Exterior angles of polygons, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your year 8 maths lesson on: Exterior angles of polygons, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
We use learning cycles to break down learning into key concepts or ideas linked to the learning outcome. Each learning cycle features explanations with checks for understanding and practice tasks with feedback. All of this is found in our slide decks, ready for you to download and edit. The practice tasks are also available as printable worksheets and some lessons have additional materials with extra material you might need for teaching the lesson.
The assessment exit quiz will test your pupils' understanding of the key learning points.
Our video is a tool for planning, showing how other teachers might teach the lesson, offering helpful tips, modelled explanations and inspiration for your own delivery in the classroom. Plus, you can set it as homework or revision for pupils and keep their learning on track by sharing an online pupil version of this lesson.
Explore more key stage 3 maths lessons from the Geometrical properties: polygons unit, dive into the full secondary maths curriculum, or learn more about lesson planning.
Licence
Starter quiz
6 Questions


Exit quiz
6 Questions






