Straightening Lines without Straightening Iron Thanks for looking this over in advance.
Hopefully pictures describe this somewhat well- but I'm looking to take the guess out of my guesswork here and have lines which are &quot;perfectly straight&quot;. Here, that means for Vertex A, B, C all on the same plane and collectively forming an Edge, with Vertex B at some point between the two others- the interior/exterior angles at Point/Vertex B are equal to 180 degrees.
Any thoughts on how to go about doing this?
In case there's a mixup, the second picture is simulating what I want to do, but that's going about it in the eyeballing way/guessing where co-linearity occurs.
Additionally I should mention that similar questions suggest scaling on an axis around a median point, which works great for lines which are perceptively straight up/down or left/right, but with this angled business the method does not appear to work as described.
You can do this with a custom orientation.

Select the A and C vertices and choose a Normal Orientation
Click the + button to save this new orientation
Select vertices A + B + C (order matters) and set pivot point to Active element
Scale the selection to 0

Making a custom orientation

Scaling to 0, active vertex as pivot point.