Fitting an arc tangentially

Goal#

Between two lines meeting at a corner an arc with a 20 mm radius is to lie that touches both without a kink — the lines themselves stay unchanged.

Steps#

1. In the triangle on the Arc button choose the Arc tang. 2+R tool (4).
2. Click the first line (1) — where the arc is meant to touch it.
3. Click the second line (2).
4. Type 20 into field R and press Enter; beforehand the preview shows the arc in the corner the mouse is in.

Result#

The arc lies tangentially against both lines. The protruding line pieces up to the corner can be removed with Trim. If that step is to be done at the same time, Fillet is the right tool — it shortens the lines and sets the arc in one go.