Build a Circle: Radius, Diameter, Circumference, Area
In the applet below, you'll see a circle. You can drag this circle's CENTER and OTHER WHITE POINT (it passes through) along the horizontal axis.
Move any 1 (or more) of the LARGE WHITE POINTS around to create a circle that meets the indicated condition. In order to do this correctly, you may need to adjust the axis scaling. You can change the scale of the axis (number increments, that is) by typing it in the input box.
For example, to scale by 0.5, simply type 0.5 in the input box, and zoom in as much as you need.
Once you create a circle that meets the condition specified, check the check box.
If you're not correct, go back and try to figure out what you did incorrectly.