Where is the center of the circle?

READ the instructions on the right and INTERACT with the GeoGebra applet below.
Click on the blue icon (upper right) to reset the diagram.

Sorry, the GeoGebra Applet could not be started. Please make sure that Java 1.4.2 (or later) is installed and active in your browser (Click here to install Java now)

Investigation Steps

  1. Look at the graphed function. Move the blue point h on the slider. How does the circle move? What changes in the function?
  2. Reset the diagram. Move the green point k on the slider. How does the circle move? What changes in the function?
  3. Reset the diagram. Move the red point r on the slider. How does the circle change? What changes in the function?
  4. Create a circle with a radius of 3 and its center is at (2,−3). What is the equation of this circle?

January 2006, Steven Lapinski. Applet created with GeoGebra.