IGCSE Maths / Working with shape and space

Finding the number of sides from an angle

Edexcel International GCSE Maths (4MA1), chapter 11: Working with shape and space, specification point 4.2d. Part of the full course.

Read the revision notes · IGCSE Maths past papers

You can find the number of sides of a regular polygon by dividing 360° by its exterior angle. If you are given an interior angle, first subtract it from 180°; the answer for the number of sides must be a whole number.

More lessons in Working with shape and space

• Angles at a point and on a line
• Angles in parallel lines
• Angle sum of a triangle
• Exterior angle of a triangle
• Angles in special triangles
• Angle sum of a quadrilateral
• Properties of quadrilaterals
• Writing geometrical reasons
• Angle sum of a polygon
• Interior and exterior angles of regular polygons
• Irregular polygon angle problems
• Perimeter and area of rectangles and triangles
• Area of a parallelogram
• Area of a trapezium
• Names of solids: faces, edges and vertices
• Surface area of a cuboid
• Surface area of a triangular prism
• Volume of a prism
• Compound prisms and volume units
• Time intervals, money and currency
• Converting units of length, area and volume