[-Skeme-]

There is no clear cut answer to determine your equity against an opponent. You must assign him a range and then go on from there. Obviously he can have many hands, and your holding differs greatly between these possible combinations of cards of his. Also, obviously this is very time consuming and insanely hard to do right then at the table. You can memorize odds charts and whatnot to give you a helping hand.

Assuming you are currently behind to a pair and are not up against another flush draw, you're about a 4.2:1 dog from flop to turn. You're currently getting 2:1 odds on your flush draw call. Obviously you aren't gettin adequate current odds from the point, so now you must rely on implied odds. You need to make up 2.2:1 in odds against your call, which is $13.30.

Do you think he'll pay off this much if you hit on the turn? Keep in mind you can easily blank the turn and check-fold to another bet.

Of course, all of this is null and void since he does not have any more money behind. Now since he's all in and you're closing the action, the answer becomes harder, since you now have outs from flop til river instead of only 1 street.

Assign him a range and run the math..