You can draw 2D circles and ellipses by using the Circle and Ellipse tools, respectively, in the Sketch menu.

Circle

Before you draw circles, choose whether you want to define circles with radii or both radii and diameters. You can do so from the Circular Annotations option in Preferences.

1. Select Circle in the Sketch menu. 
2. Click to add the center and circumference points. You can also type the radius or diameter to quickly define the length. 
3. Finish the sketch by pressing Return. 
   If you want to remove the shape, then press one of the following:
   • Delete
   • Escape
     Or, secondary click (right-click) with your mouse. 
4. Press the Escape key to drop the active sketching tool. 

When you select the drawn circle or its dimension label, you can see the radius or diameter, depending on your Circular Annotations setting.  

Ellipse

1. Select Ellipse in the Sketch menu. 
2. Click to add the center and circumference points. 
3. Finish the sketch by pressing Return. 
   If you want to remove the shape, then press one of the following:
   • Delete
   • Escape
     Or, secondary click (right-click) with your mouse. 
4. Press the Escape key to drop the active sketching tool.