calculating slope of a DEM or TIN

Hi All,

I have been tasked with finding a way to make a few calculations using a DEM or TIN in an ArcServer application, these calculations are to Draw a line and calculate the slope based on the DEM or TIN, and 2 is to draw a polygon and calculate the facing angle and slope of a best-fit plane through that surface.

I know it has to do with spatial analyst and some sort of geoprocessing service, could anyone help me out here?

After this is  built it is possible to run a geoprocessing task from a workflow correct?

Thanks!