Question 213444
The center is at (0,0) and the radius is r.  That's it!!


If you need additional help with Circles, you may want to check out my website by doing a "Bing" search for my last name "Rapalje". Look for "Rapalje Homepage" at the top of the search list, and choose the link on my homepage "Math in Living Color." Click on "College Algebra", and look for Section 2.04 "The Circle" at this link.  My non-traditional explanation should be easier to understand than your textbook! 


R^2 


Dr. Robert J. Rapalje, Retired
Seminole Community College
Altamonte Springs Campus
Florida