IGCSE Maths / Working with shape and space

Writing geometrical reasons

Edexcel International GCSE Maths (4MA1), chapter 11: Working with shape and space, specification point 4.7a. Part of the full course.

Read the revision notes · IGCSE Maths past papers

Geometrical reasons explain why each angle step is true. To earn the reason marks, name the shape or angle relationship and state the full fact, once for every line of working.

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
• Angle sum of a polygon
• Interior and exterior angles of regular polygons
• Finding the number of sides from an angle
• 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