The MASSPROP command will give you the section properties that you desire. Simply draw your section and then convert it into a 2D region. Run the MASSPROP command, and you will have the answer. Be careful, because the MASSPROP command gives the properties relative to the origin of the UCS. Therefore, either move your UCS or the region so that the C.G. of the section is at 0,0,0. Since MASSPROP gives you the C.G. location, this is easy to do in a 2 step process.