This shows the result of composing two dilations (enlargements): A, then B.
Dilation A is represented in blue: you can change the centre and the scale factor.
Dilation B is represented in red: you can change the centre and the scale factor.
The check boxes alter what you see.
You can see the result of dilation A (initially hidden), arrows which show what happen to the vertices of the quadrilateral (initially shown) and lines which demonstrate whether or not the composition really is a dilation (initially hidden).
Is the composition of two dilations also a dilation? If so, where is the centre?

You can:
* Investigate when happens when the quadrilateral is moved.
* Decide whether or not the composite transformation is or isn't a dilation, and if so where the centre of the dilation is.
* Investigate what happens when the centres of each individual dilation are moved.
* Investigate when happens when the scale factors of each individual dilation are moved.
This interactivity was inspired by a tweet by James Tanton.