Problem with extruding 2D Shape in Inventor

Can not extrude a 2D shape that is drawn by lines.It appears to be linked but is not .I can see the problem saying not a closed loop or a constraint but don't know how to fix it.

Helping out one engineer.

6 Answer

This is another way of getting the problem resolved - This way is for complex sketch shapes.

what you have are floating lines. Go edit sketch and use coincident constraint to join the end points and you should be fine.

You will get a tell tale sign before you even start to extrude,like autocad you get prompts at the bottom of screen,with inventor it will tell you its not fully constrained or you need more dimensions,this is just for other people who may look at this,just to say theirs always dialogue going on between you an the software but thats not to say we dont miss the obvious sometimes,no disrespect intended as I m in that group too!

Thank you ALi and William, your answers were really helpful to me!!

So it is very easy..