IGCSE Maths / Transformation and similarity

Congruence under transformations revision notes

Edexcel International GCSE Maths (4MA1), chapter 14: Transformation and similarity, specification point 5.2i. Part of the full course.

Watch the video lesson · IGCSE Maths past papers

Congruent shapes have exactly the same shape and size. Translations, rotations and reflections preserve all lengths and angles, while an enlargement usually changes lengths.

More lessons in Transformation and similarity

• Lines of symmetry and rotational symmetry
• Equations of common mirror lines
• Reflecting a shape in a line
• Reflecting in y = x and y = -x
• Finding the mirror line from object and image
• What defines a rotation
• Rotating a shape about a point
• Positive and negative rotation angles
• Rotating about a point not on the shape
• What defines a translation
• Translating a shape
• Column vectors in translations
• Describing a single transformation fully
• Combining two transformations
• What defines an enlargement
• Similarity under enlargement
• Enlarging from a given centre
• Fractional scale factor enlargements
• Finding the centre of enlargement
• Conditions for congruent triangles
• Proving triangles are congruent
• Similar shapes: corresponding lengths
• Area scale factor
• Volume scale factor
• Similar solids, mass and capacity
• Similar shapes problem solving