Coming off their penalty-plagued blowout win over the Lions, the Vikings stayed at home and met in a Week 11 duel with the Seattle Seahawks. After a scoreless first quarter, the Vikings got on the board with QB Brett Favre completing a 23-yard TD pass to wide receiver Percy Harvin. Later in the same quarter, the Vikings increased their lead with an 8-yard TD pass from Favre to tight end Visanthe Shiancoe. Closing out the first half was a 3-yard TD pass from Favre to wide receiver Bernard Berrian to make a 21-0 Vikings halftime lead, the first time of the season the Vikings kept their opponent scoreless in the first half. In the third quarter, the Vikings continued to dominate as Favre found wide receiver Sidney Rice on a 7-yard TD pass. Seattle scored their first points of the game when kicker Olindo Mare nailed a 40-yard field goal. Finally, the Vikings put the game away as second-string QB Tarvaris Jackson found Rice again on a 34-yard TD pass. The Seahawks tried to rally with a 1-yard TD run by running back Justin Forsett (with a failed 2-point conversion), but the Vikings prevented the Seahawks comeback from advancing any further. With the win, the Vikings improved to 9-1. Brett Favre threw 4 TD passes for the 22nd time in his career (second of the season), breaking the mark set by Dan Marino.
Question: How many points did the Vikings lead with by halftime?
Answer: 21