I'm trying to remove a rounding in a green-filled path. I'd like there to be a node positioned exactly in the top right corner of the dashed box encompassed by the black circle in the below image. Is there a way to get a node in that spot?

Perhaps like this?



Note the snap settings.

Snapping is one of the best ways to precisely place a node, and there are many options, including grids and guides to name a couple. http://tavmjong.free.fr/INKSCAPE/MANUAL ... pping.html

You can also use the Node tool control bar, and set the precise x and y coordinates.

I would suggest following a few tutorials, to learn some of these ways. Tutorials are all over the internet, including the Inkscape website (inkscape.org) but I try to maintain a central list here: https://forum.inkscapecommunity.com/