SOLIDWORKS infers from the pointer motion whether you want a tangent or normal arc. There are four intent zones, with eight possible results as shown. Moving the pointer in a tangent direction creates a tangent arc. Moving the pointer in a normal direction creates a normal arc. You can toggle between tangent and normal arcs by returning to the end point and moving away in a new direction.
![sketch_tangent_arc_intent.gif](iek1450448090449.image)
Video: Sketching Tangent Arcs