Properties of Shape - Angles in Regular Polygons - Planning

This Year 6 lesson is part of a series on the Properties of Shape, focusing on angles in regular polygons. The lesson begins with a recap of previous knowledge about shapes, leading into the first activity where students draw a quadrilateral and partition it into two triangles. Through paired discussions, they explore the sum of interior angles in triangles and extend this understanding to quadrilaterals, establishing that a quadrilateral's interior angles total 360°. This concept is reinforced by demonstrating that since a quadrilateral can be divided into two triangles, and each triangle's angles sum to 180°, the quadrilateral's total is simply double that of a triangle. The lesson's second activity challenges students to complete a table, using the method learned to calculate the sum of interior angles for various polygons, and encourages them to predict angle sums for other shapes. This leads to the discovery of a formula for the sum of internal angles in any regular polygon, which is the number of sides minus two, multiplied by 180°.

During group work, students discuss and share answers to reasoning questions, applying their knowledge to different scenarios. Independent learning is supported by differentiated worksheets that focus on fluency and reasoning. Key questions prompt students to consider the differences between regular and irregular polygons, the pattern in calculating interior angles, and how to predict angle sums. The plenary session addresses common misconceptions and reinforces the method of partitioning polygons into triangles to calculate angles. The lesson concludes with a reflective 'Give me five' activity, where students consider what they have learned, the skills they've used, and what they found challenging, ensuring they remember the methods taught. Differentiated outcomes are provided for varying levels of understanding, from working towards fluency to achieving greater depth, with the aim of enabling all students to calculate the sum of angles in polygons split into triangles.