IGCSE Maths / Transformation and similarity

Positive and negative rotation angles

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

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The sign of a rotation angle tells you which way the shape turns: positive is anticlockwise and negative is clockwise. A clear rotation description gives the angle, direction and centre, except that a half turn does not need a direction.

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
• Rotating about a point not on the shape
• What defines a translation
• Translating a shape
• Column vectors in translations
• Congruence under transformations
• 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