How do I know what my win % is.

[R3M0T3]

Say I have a brunson in the big blind 10 [img]/images/graemlins/club.gif[/img] 2 [img]/images/graemlins/diamond.gif[/img]

A middle player and cuttoff call and the small blind completes

Flop comes
10[img]/images/graemlins/heart.gif[/img] 9 [img]/images/graemlins/heart.gif[/img] 4 [img]/images/graemlins/spade.gif[/img]

So I have top pair crappy kicker

sb bets

there are now 5 bets in the pot
I may well currently have the best hand
In fact pot odds are giving me 5:1 or 16.67%

How do I know that my hand will win more than 16.67% of the time to make this call a profitable call?