Answer based on context:

The Redskins traveled to Texas Stadium in Irving, Texas to take on one of their NFC East rivals, the Dallas Cowboys in a Sunday Night match-up.  The Redskins trailed early, as Dallas kicker Mike Vanderjagt completed a 26-yard field goal and Drew Bledsoe completed a 4-yard TD pass to WR Patrick Crayton in the first quarter.  In the second quarter, kicker John Hall would get Washington a 39-yard field goal, but Dallas responded with RB Marion Barber's 1-yard TD run.  RB Rock Cartwright would return a kickoff 100 yards for a TD, but that would be the last time in the entire game that Redskins would score a single point.  Even though there wouldn't be a single point scored in the third quarter, the Cowboys sealed the win with a 40-yard TD pass to WR Terry Glenn and a 50-yard field goal by Vanderjagt. With the loss, the Redskins dropped to 0-2. Stats

How many yards was the longest field goal of the game?
50