V. DRAW Menu
C. Circle
There are several ways to graph a circle on the TI83. You can graph a circle in rectangular mode, parametric mode, and polar mode. However, these all require that a function or functions be entered. If you want to just draw a circle, you can do it through the DRAW menu, but it will just be a drawing of a circle and TRACE, TABLE, CALC, etc. do not apply.
Example: Draw a circle of radius 8 with center at (2,2). Use a square window by entering [Ymin, Ymax] and then ZSquare.
Set [Ymin, Ymax]=[8,10]
and then enter ZSquare. 
Access DRAW Circle.

Enter the center
and then the radius. 
Press ENTER.

To delete the circle, enter 1.