Double-click on the movie to PLAY.

Click once to PAUSE.

RELOAD the page or double-click to return to the START of the movie.

**Method C1**

Here we start with the multiplier 1.2 but gradually increase it to 2, ie we consider the locus of P as *r* changes from 1.2 to 2 in the relationship AP = *r* x BP. Again, we assume AB = 2 units.

Before running the movie it is worth asking

- what happens to the locus (ie the size of the circle) as *r* increases from 1.2 to 2 ?

- what is the diameter of the circle when *r* = 2 ?

After running the movie, it is worth asking

- what would happen to the locus if we made *r* larger and larger?

- what would happen to the locus if *r* was less than 1.2 ?

On the next page we consider values of *r* from a maximum of 4 to a minimum of 1/4 (ie 0.25).