Calc QUestion!!!! Need help on graphing

I messed up on the graph need a lil help on what i did wrong thanks. :)

http://www.flickr.com/photos/54816444@N02/6209762252/

What you sketched is the graph of z = sqrt(x^2 + y^2), but your given equation is z^2 = x^2 + y^2, so you are missing the part z = -sqrt(x^2 + y^2) that is the reflection of your sketch on the negative z-axis.