1. select the face
2. select the scale tool R-key
3. goto tool settings and select - Set to Edge
4. select an edge radiating out (ie perp to the direction your wish to scale)
Now this will work for 1 radial arm. If you are trying to create a symmetric shape you will have another problem and that is once you scale one arm, you have altered the two adjacent arms at the hub and the edges on the top for those two arms are no longer parallel.
Can you describe the final shape you are trying to get too?
If you are trying to create a symmetric shape Maya does not have Action Centers like LW, Modo, and Max so you cannot do it is a single step.
You would have to isolate one arm and scale it. With the pivot at the center you'd press shift-d and then rotate the duplicate arm 60'. Then press shift-d to repeat the duplicate and rotate operation four more times. Finally, you'd combine everything and fill in the central hub section.
Maya's modeling tools have not been updated for a very long time and Autodesk appears to not consider them to be a priority. The other option for this problem would be a script but the time to write that would not be worth it really.
"If I have seen further it is by standing on the shoulders of giants." Sir Isaac Newton, 1675
Last edited by ctbram; 07-12-2012 at 12:23 PM.