change angle of a new line in relation to another line that the new line connects to

Hi Robert,

you could use snapping to grid to get exact angles (i.e. create a grid with the angles you need and snap the nodes to the grid). Or you could create a circle segment (enter its start and end angle in the circle tool's tool bar) and use that for snapping.

If the angles do not need to be 100% exact, you can just look at the status bar while you are drawing (it will show you length and angle of the current path segment). Or you can use the measure tool to measure the angles and correct them if needed.

If you need to do this kind of thing regularly, and the angles need to be perfectly exact, you should also have a look at some CAD software. Inkscape is a drawing software, mostly used and intended for artistic drawings, and doesn't come with a lot of CAD functionality (although it is always possible to get what you want if you know the tricks).

Kind Regards,
 Maren