What is the Evolutionary Advantage?

We have 5 fingers, not 4 or 6.

Starfish and Echindodermata, the other phylum in the deuterostomes, have pentaradial symmetry.

So I ask you, /sci/, what is the EVOLUTIONARY ADVANTAGE of five?

There are four and six-armed sea stars, you know. We should make them fight and see why the five armed one wins. I'm betting it gives an advantage when doing the Texas piledriver.