There are many interesting ways to fill in the blank. My choice is:

```
int count = 1;
while ( count <= 10 )
{
circ.setRadius( (100/10)*count );
circ.draw(gr);
count = count + 1;
}
```

Since the width (and height) of the drawing area is 200, circles can have a radius of up to 100. For ten circles, that maximum radius is divided by ten to give the size increase in each radius.

Here is what the applet draws: