Power of the in position 3 bet

Full Tilt Poker $0.25/$0.50 No Limit Hold'em - 6 players - http://www.thehandconverter.com/hands/329803
The Official DeucesCracked.com Hand History Converter

MP: $10.45
CO: $10.70
Hero (BTN): $51.85
SB: $42.05
BB: $67.40
UTG: $50.00

Pre Flop: ($0.75) Hero is BTN with 7d 7c
UTG raises to $1.50, 2 folds, Hero raises to $4.25, 2 folds, UTG calls $2.75
UTG has been a very active player. I don't have the stats on him (at the time of this writing), but his open range is somewhere around 20. Therefore, I 3 bet him in position.

Flop: ($9.25) Ks 6c Ah (2 players)
UTG checks, Hero bets $4, UTG folds
Dry flop and he checks. I'm going to stab with a probing cbet. A raise or call from him means I give up. I'm assuming he may have been good here; he called a 3 bet out of position - I give him credit for pocket pairs. Given the way he's been playing, he's not folding inside draws (QJ QT JT), particularly for an under half pot bet... I don't think he's folding a King outright on the flop, and he certainly is not folding an Ace. That leaves us with TT, 99, 88 and less. My guess is he had 88.

Final Pot: $9.25
Hero wins $8.80
(Rake: $0.45)