Sketcher > Creating Sketcher Geometry > Points, Centerlines, and Coordinate Systems > Construction Points, Centerlines, and Coordinate Systems > To Create a Construction Centerline Tangent to Two Entities
  
To Create a Construction Centerline Tangent to Two Entities
1. In the Sketching group, click Centerline Tangent.
2. Select a start location on an arc or circle. An endpoint is created.
3. Select a location on another entity for the second endpoint. The centerline is created.