Expanding Circle: Area changes with respect to the radius

Author:
aggiemath
Topic:
Area, Circle
An expanding circle with a slider that adjusts the radius. On left-hand side, one can see how the area changes with respect to the radius, where dArea represents the rate of change of the area with respect to the radius.
How does the area of the circle change with respect to the radius when the radius is 3? Use the applet to visualize and check yourself.