# Reasoning about angles in polygons

I can reason about the sum of the angles within different polygons.

# Reasoning about angles in polygons

I can reason about the sum of the angles within different polygons.

## Lesson details

### Key learning points

- Angles describe and measure a turn or rotation.
- Protractors can be used to measure and draw angles.
- Use knowledge of right angles to estimate and compare angles.

### Common misconception

Pupils think that composing larger polygons of smaller triangles that are not formed as a result of drawing a line from one vertex to another will help them to identify the sum of the angles.

Highlight how the formation of triangles within a polygon must be from vertex to vertex and demonstrate how the angles of each triangle where they meet sum to the internal angle of the polygon.

### Keywords

Angle - An angle is a measure of turn.

Sum - The sum is the result of adding two or more numbers.

Vertex - A vertex is a point where two or more lines meet.

Polygon - A polygon is a 2D shape made up of three or more straight lines.

### Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

## Video

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