Angles in triangles

I know that the angles in a triangle sum to 180°.

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Year 5

Angles in triangles

I know that the angles in a triangle sum to 180°.

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Share activities with pupils

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Lesson details

Key learning points

Angles on a straight line sum to 180 degrees.
Interior angles in triangles sum to 180 degrees.
Missing angles can be calculated using the sum of 180 degrees.

Keywords

Quadrilateral - A quadrilateral is a polygon with four straight sides and four vertices.
Triangle - A triangle is a polygon with three straight sides and three vertices.
Sum - The sum is the result of adding two or more numbers.

Common misconception

Pupils struggle to remember the number of degrees in a triangle as they only know it as a disconnected fact.

Apply pupils' knowledge of angles in a quadrilateral to understanding the sum of the angles in a triangle. Spend time showing how a quadrilateral is constructed using triangles and what happens to the angles as the quadrilateral is partitioned.

It is important that pupils are provided with opportunities to construct triangles for themselves. Using angle tools to help construct triangles is an appropriate step to make use of before moving to drawing angles with a protractor in later lessons.

Teacher tip

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).