Relative start

 From:  Rozen (ROZENS)
628.1 
I would like to know if theres a way of start to draw or place objects from a relative position....?
I have figured out to use the construction lines, but I need to put in exactly numbers...example.: start to draw 5mm in one direction, and 5 mm in another direction, from a relative point, or maybe even in the third direction...?

Thank you in advance!
Rozens