The dial table shows a front arc and rear arc on the top left corner of the window (that is when i click on Dial of each character on Wizkids' website). What are these for? I didn't come across any rules about it. For example, Professor X's Front Arc is stated 360. Is there a significant meaning? Does it affect gameplay?

The arcs are game mechanics from some of the WizKids games, but they don't play a part in HeroClix. And in the website design, they're just there as a holdover from Mage Knight, really.

Ah I see. Thanks.

In Mageknight the Arc is the point of view of your fig.

if another figs walks behind him he cannot see him (so he can't shoot at him), which means you msut place your figs carefully.

Heroclix doesn't have that (or heros villains are smart enough to turn around) for simplicities sake.