There are two instances in particular where I need to be able to do this.
First, I have a set of objects, that are in a line, that I need to rotate to an arbitrary/unknown angle. In the graphic below, I need to get the circles rotated around the bottom right corner such that their center point is on the dashed red line.
Second, I layout designs to be cut on a laser cutter, so often I need to know the length of an arbitrary line(usually the diagonal of a rectangle), so that I can craft other parts to match them. To measure them, I rotate it to either 0 or 90 and take a look at the object properties. Yes I could use good ole pythagoras' theorem, but I'd rather not have to pop out of the program, if possible
