1
Select the Create Rounded Corner tool 
from the Sketch ribbon
group.
2 Click a line or arc.
3 Mouse over another line to preview the fillet that will be created.
If you mouse over a line that is the edge of a solid, that edge will not change. Only a sketched line will change. The radius of the arc is previewed as you move the mouse. Enter a radius to dimension it.
4 Click an intersecting line to trim the lines, or a non-intersecting line to connect the lines.
Where you click on the intersecting line defines the radius of the tangent arc, or you can dimension the round by entering its diameter.
If the lines intersect, click the part of the intersecting line you want to keep. If the lines do not intersect, you can click anywhere on the line to extend the lines to form a rounded corner. Circles are never trimmed.
