The ellipse tools are responsible for creating Ellipse Entities.
Find one of the ellipse tools icons 
on the Entity Toolbar (color coded blue) and click on the tool. The tool is now active and ready for use. This set of tools is part of a Flyout toolbar.
There are four different method that can be used to create an arc entity.
1. Center-Radius Ellipse Tool: This tool is used to draw ellipse entities by specifying the center point and then the major and minor axis.
2. Quadrant-Quadrant Ellipse Tool: This tool is used to draw ellipse entities by specifying opposite points on the ellipse.
3. Elliptical Arc Tool: This tool is used to draw an ellipse (using the Center-Radius method) and then to turn it into an arc by specifying the angle at which it starts and ends.
Also See:
Ellipse Entity
Flyout Toolbar
