- Definition
Dilation is when you make a shape bigger or smaller, but it still looks exactly the same, just like zooming in or out on a picture.
Enlarging a 2x3 rectangle by a scale factor of 2 results in a similar 4x6 rectangle.
How to teach this in 30 seconds
Try this analogy: A dilation is like using your fingers to pinch and zoom on a photo on a phone — you're making it bigger or smaller without changing its shape.
Ask your child: If we double the size of this drawing, what changes and what stays the same?
Common mix-up: Kids often think dilation only means making something bigger. A dilation can also shrink a shape, as long as the new shape is proportional to the original.
Examples
- A map is a dilation of a real geographic area, reduced by a very large scale factor.
- Reducing a triangle with sides of 9 and 12 by a scale factor of 1/3 creates a similar triangle with sides 3 and 4.
dilation is a term used in Ontario’s Kindergarten to Grade 8 curriculum.
Where this shows up
The descriptions on this page are SmartStudy’s own original, plain-language writing — not the Ministry’s wording. They are aligned to the Ontario Curriculum, © King’s Printer for Ontario. For the Ministry’s official wording, see the source link below. SmartStudy is an independent service and is not affiliated with, endorsed by, or sponsored by the Government of Ontario or the Ministry of Education. Ontario Curriculum and Resources ↗
