Use this to try drawing perfect circles. You can translate a standard form of a circle (precal terms) to the h, k, and r values. If your values are below 10, it is more visually assisting to use multiples of 10. Like, if your h is 4, use 40 instead. Also, use turbo mode. This tool could help you with your graphing, too. Press Z to turn on Picture Mode. Press X to turn it off.
Update 1/22/17: Now, you can get the standard form equation for your circle. It's more practical to use the original numbers, not the exapanded ones. For example, if your actual radius was 4, and you used 40, use 4 if you want the correct equation. Update 1/21/17: If you want it to draw an absolutely perfect circle, look inside the pen sprite and change pen size from 2 to 1. If you want a smoother looking circle, but just a hair off of the absolutely perfect circle, set it to 2. 2 is only slightly off, so you are unlikely to notice it anyway. It just adds 1 pixel to the edge of the circle. Note: Radius values greater than 160 will never look right and will have lots of white space. So I've started dual credit for college and am working with circles currently. I created this just because. This took me 5 minutes to throw together a basic circle-drawing system, and 20 minutes to add all the bells and whistles (center point dot, xy grid, fill/nofill, changeable color). It originally filled the circle by default, and I added a bit that would show you the exact center point.
