Drawing Lines at Specified Angle

Hello all, new user here. 

 

Can't find anything in the docs that tells how to draw two lines at a specified angle i.e. the angle would be entered on the command line.

Also, when I draw a circle and attempt to draw a circle concentric to it, nothing happens after specifying the centre point for the second circle (I have to draw the second circle elsewhere and move it to the centre of the first).

Thanks for any help...