[wiggs73]

600*3 pre-flop. 400*2 on the flop, plus the 1200 raise. So the pot is at t3800 and it costs you 800 to call. 3800/800 = 4.75 so you're getting 4.75:1 on your money.

You have 6 outs for a straight. There are 52 cards in the deck - 2 in your hand - 2 in his hand - 3 on the board. 45 cards left. That leaves 39 cards that don't help and 6 that do. 39/6 = 6.5. 4.75 < 6.5 so don't call.

Your odds would change if you had 2 shots at catching the straight, but it's highly unlikely that you will after that raise, so I didn't factor that in.