Hello,

I'm start out to work with SolidWorks and trying out tasks from this link http://ftp.deu.edu.tr/SolidWORKS/Alistirmalar.pdf

However I have problem with extrusion. I made 3 concentric circles they are fully defined and i extruded one circle (shown in picture), however now it doesn't let me extrude second one (option greyed out) what could be the problem?