Congruency, Enlargement and Combined Transformations
Enlargement
A transformation that changes a shape’s size by a scale factor while keeping its shape.
| English | Enlargement |
|---|---|
| Bahasa Melayu | Pembesaran |
| 中文 | 放大 |
How it is used
Enlarge triangle with vertex A(1, 1) about centre O(0, 0) with scale factor 3. The image vertex is A′(3, 3), because each coordinate is multiplied by 3 from the centre.
Where it shows up in SPM
A key transformation in this Form 5 chapter. Paper 2 asks you to draw the image given a centre and scale factor, describe an enlargement fully (centre and scale factor), or use k² to relate object and image areas.
It also appears as one step inside a combined transformation.
Don't confuse it with
Open the chapter: Congruency, Enlargement and Combined Transformations →
Frequently asked questions
Is an enlargement always bigger?
No. When the scale factor is between 0 and 1, such as k = ½, the image is smaller than the object even though the transformation is still called an enlargement.
Only k greater than 1 makes the image larger.
How do I fully describe an enlargement?
State two things: the centre of enlargement (as coordinates) and the scale factor. For example, an enlargement of centre (0, 0) with scale factor 2.
Miss out either part and you lose marks even if the drawing is right.