Hello old Sailor, welcome to the group!
....Maybe not a show-stopper, probably more of a ROAD-BLOCK!....
(hint...hovering over a function icon allows you to see its description)
If you are creating an angled line first go to the line tab, then select "draw an angled line". The prompt at the bottom left of the screen will prompt you for three actions...
1) to place the line at the starting point of the angle
2) the actual angle desired (enter angle then press ENTER)
3) the overall length of the line (enter length then press ENTER)
this will not create an angle between two lines, instead it will simply create a single line at that angle. (just as you mentioned...0