To Create an Arc
1. On the Sketch tab, click the arrow next to Arc, and then choose a method of creation:
◦ Click 
3 Point/Tangent End and select the first point on the arc circumference.
3 Point/Tangent End and select the first point on the arc circumference.◦ Click 
Center and Ends and select a point for the center of the arc. A construction circle appears.
Center and Ends and select a point for the center of the arc. A construction circle appears.◦ Click 
Tangent and select an arc, circle, ellipse, or line at the tangency point to set the first point of the arc.
Tangent and select an arc, circle, ellipse, or line at the tangency point to set the first point of the arc.◦ Click 
Concentric and select a circle or arc, or the center point of a circle or an arc, as a reference for the center point of the arc. A construction circle appears.
Concentric and select a circle or arc, or the center point of a circle or an arc, as a reference for the center point of the arc. A construction circle appears.When you select a creation method, the location of the start point is displayed, relative to the base point.
2. Select more points as needed to size and position the arc.
3. To lock the one of the dimensions of the entity you are creating, press Enter. Press Tab to switch to the other dimensions.
4. Middle-click to exit the tool.