I'm not sure what you are going for so...
If have an arc that you want to continue into a straight line, once the arc is done with the

do a convert to path then select the arc with

. Black boxes will appear on the end of the arc. Then select

. Start the straight line on the black box and it will be a continuation of the arc in one path.
If you want to make arc like in the image above use the

and the round handle to make an arc. If you want to connect two arcs like in your image. Draw the two arcs. Turn on snap nodes to nodes in Documents properties
shift ctrl D >> snap tab. With snap the end nodes will snap to each other then do a combined under paths menu to get one path. If you are talking about the aesthetics of making a sharp angle in inkscape, I usually have to put in 2 or 3 nodes to get a curve that doesn't look kludgey. Followed by a lot of node tweaking. And use a mix of corner and round nodes. It might be different if you are on a drawing tablet. The

in default mode uses
Bézier curves which too me aren't always the most attractive curves. If you are on Windows or Linux you could try the new feature Spiro mode on the

in the developers version.