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# Topic 10 Year 8 Mathematics

 Mathematics Topic Angles in polygons No of lessons 12 When is it happening Term 3 Year 8 What will students learn Students use their understanding of angles in triangles from year 7 to build up to a proof for the sum of the interior angles in polygons with 4 or more sides by dividing into triangles. The perspective is then shifted to investigate the sum of the exterior angles of a polygon and students develop an understanding of the relationship with between the exterior and interior angles. Students solve a variety of problems using the angle relationships built up in this unit and in previous units. Key Knowledge that students should know at the end of 'Topic' This is the knowledge that students will meet for the first time in this topic Know the sum of interior angles of a triangle and use to solve angle problems (revise from Year 7) • Explore different methods for finding the sum of the interior angles of polygons by splitting the shape into triangles • Generalise different methods for finding the sum of interior and define the sum of the exterior angles of a polygon • Use the sum of the interior and exterior This is knowledge that students may have met before but will need to deepen their understanding Review angles including angles in parallel and perpendicular lines. Key Skills that students should be able to demonstrate at the end of 'Topic' This is the skills  that students will meet for the first time in this topic using a protractor This is skills that students may have met before but will need to develop Drawing different types of angles Key vocabulary that students should know and understand Adjacent, vertically opposite, exterior, interior, polygon, The Big Question What do the interior angles in a polygon sum to? Key questions that students should be able to answer at the end of the 'Topic' What is a regular polygon? Can I find missing angles in isosceles triangles? What are the angle rules? What do angles in a pentagon sum to? What is an icosagon? Can I find missing angles in a pentagon? How do I find exterior angles of polygons? Can I use the sum of the exterior angles to find individual angles? Are exterior angles in triangles always the same? Can I find missing angles in triangles?