I am trying to make steel panels but when I do the sketch and try to extrude it I cant. I make sure all lines are joined. The panels are joined V shaped. I cant seem to snap to the grid either. Please keep in mind I am self taught at this Inventor so It could be a stupid question. Is there not a poly line feature I can use? How can a turn a shape into a polygon?

Thank you for your time people and Happy Holidays to you

My guess is that you are using Inventor 2010 and have accidently turned off Constraint Persistence or Constraint Options.
You might read this document http://home.pct.edu/~jmather/skillsusa%20university.pdf
 
There is no polyline in Inventor as it is not needed.  If you really want a regular equal sideded polygon use the Polygon tool.
 
Zip and attach your file here so that someone can determine why it will not extrude.JDMather2011-01-02 16:06:19