GCSE Maths Angles, Polygons and Symmetry: lesson and practice questions

By the end of this chapter you will be able to

• Use the correct words and notation for points, lines, angles, polygons and triangles
• Use angles on a line, angles around a point and vertically opposite angles, and give reasons
• Find missing angles in triangles, including isosceles and equilateral triangles
• Use alternate, corresponding and co-interior angles on parallel lines
• Know the properties of the special quadrilaterals and use their angle sums
• Calculate interior and exterior angles of polygons and regular polygons
• Find lines of symmetry and the order of rotational symmetry
• Solve angle problems with algebra and write clear reasons (Higher: geometric proof)

You should already know

• Measuring and drawing angles with a protractor
• Solving simple linear equations (Chapter 9)
• Basic names of 2D shapes

Where this leads

• Pythagoras and trigonometry (Chapter 20)
• Congruence and similarity (Chapter 21)
• Circle theorems (Chapter 26)