I'm not sure if I fully got your problem, but here are some thoughts:
- you can draw a circle in the rotation center with a radius of wanted line length and use snap to intersection to draw or rotate the wanted line
- draw another circle in the ray center, with a wanted offset to the outer circle, passing the intersection point and use snap to intersection
- for multiple lines, construct one of them and then use rotation tool with multiple copies and keep original to multiply it
Armin
investing less than half an hour into Search function can save hours or days of waiting for a solution