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Transformations
Chapter summary, hard words and model exam answers for ICSE Class 10 Hindi.
Free online summary and notes (ICSE Class 10 Hindi). Read it here, no PDF download needed.
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Mathematics · CBSE 10 · ICSE 10 · GCSE (AQA, Edexcel, OCR)
Summary
Reflect in y = x by swapping coordinates: (a, b) → (b, a). To describe a rotation you must give the centre, the angle, and the direction.
The top number moves right (or left), the bottom number moves up (or down). The image is congruent to the object.
SF greater than 1 makes it bigger; SF between 0 and 1 makes it smaller; a negative SF also flips it through the centre. The image is similar to the object.
A combined transformation can often be replaced by one equivalent transformation, which exam questions ask you to describe fully.
Hard words & meanings
| congruent | identical in shape and size; mapped onto each other by reflection, rotation or translation alone |
| similar | same shape but not necessarily same size; equal angles and sides in the same ratio |
| scale factor | the number all lengths are multiplied by in an enlargement; a negative one also inverts the image |
| centre of rotation | the fixed point a shape turns about; every other point traces a circular arc |
| centre of enlargement | the fixed point from which all distances are measured and scaled |
| column vector | two numbers stacked vertically: top = horizontal shift, bottom = vertical shift |
| isometry | a transformation that preserves all distances and angles, so the image is congruent |
| mirror line | the line a shape is reflected across; each point and its image are equidistant from it |
Model exam answers, grammar & audio
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