This shows the result of composing two dilations (enlargements): A, then B. [br][br]Dilation A is represented in blue: you can change the centre and the scale factor. [br]Dilation B is represented in red: you can change the centre and the scale factor.[br][br]The check boxes alter what you see. [br]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).[br][br][b]Is the composition of two dilations also a dilation? If so, where is the centre?[/b]

You can:[br]* Investigate when happens when the quadrilateral is moved.[br]* Decide whether or not the composite transformation is or isn't a dilation, and if so where the centre of the dilation is.[br]* Investigate what happens when the centres of each individual dilation are moved.[br]* Investigate when happens when the scale factors of each individual dilation are moved.[br][br]This interactivity was inspired by [url=https://twitter.com/jamestanton/status/567307177589620737]a tweet by James Tanton[/url].