Toolbar / Icon:
Menu: Draw > Line > Relative Angle
Shortcut: L, R
Commands: linerelativeangle | lr
Create lines with a relative angle to existing entities with this tool. The existing entity can be a line or an arc / circle. Lines with a relative angle of 0 degrees to an arc are tangents or parallels to tangents. Lines with a relative angle of 90 degrees to an arc or line are orthogonal lines.