Interior angles of a polygon
I can find the interior angle of any polygon.
Interior angles of a polygon
I can find the interior angle of any polygon.
These resources will be removed by end of Summer Term 2025.
Lesson details
Key learning points
- Any polygon can be split into triangles.
- Using these triangles you can demonstrate the rule for the interior angle sum of a polygon.
- A missing interior angle in any polygon can be found.
Keywords
Polygon - A polygon is a flat (2D), closed figure made up of straight line segments.
Interior angle - An interior angle is an angle formed inside a polygon by two of its edges.
Sum - The sum is the total when numbers are added together.
Common misconception
When splitting a polygon into triangles, pupils may draw line segments that cross inside the shape.
By choosing a single common vertex for all the triangles, the line segments will not cross inside the shape.
To help you plan your year 8 maths lesson on: Interior angles of a polygon, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your year 8 maths lesson on: Interior angles of a polygon, 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


