Set line length in Inkscape

Question

I want to set the length of the red line to be 0.5". (Actually, the svg doesn't export the red, so let's say the one that points to 4 o'clock.)

How do I do that?

Answer 1

Another, possibly quite precise option, using the measurement tool:

https://youtu.be/lcYv5dLTScU

Answer 2

create orthogonal reference line of approximate desired length

(hold control while creating line) and adjust as needed in appropriate width field.

note: size in mm equals one-half inch

change color and increase width of stroke for ease of use

reduce opacity for same reason

place new line on separate layer for ease of destruction

drag horizontal and vertical guides to intersect node of line at static end note: ensure that the guides are intersecting the node/snapping to them

drag new line to snap to line to be changed at static end

click on new line to change to rotate mode

note pivot crosshairs

drag pivot crosshairs to intersection of guides

note: use maximum zoom to ensure the rotation center is on the node/guide intersection. I've not been able to locate a resource which permits the rotation center to snap to anything

Note that the rotation center is not at the guide intersections, as it disappears when placed there. For the purposes of this presentation, it's close enough to see and the answer states to place it on the dot, so to speak.

rotate new line at optimum zoom to align with existing line

There is no snapping going on here, but at a good zoom level, one can use TLAR to ensure that the lines are parallel. (That looks about right).

select existing line in node edit mode

snap existing line end to new line end

I've rotated the newly adjusted line to horizontal by eyeball and note that the dimension field shows the desired 12.7 mm length.

delete layer/new line as desired

There may be an easier/better way to accomplish this. My first thought was to create the line length necessary and place and rotate it, but that's not how the question is phrased.

One could eliminate the guides, but that reduces a bit the "precision" available to place the rotation crosshair, especially at maximum zoom.