The clinching question? "Because Earth bulges at the equator, the point that is farthest from Earth's center is the summit of a peak in Ecuador. Name this peak." Sathwik nailed it: Chimborazo.
Runner-up Conrad Oberhaus, 13, of Lincolnshire, Ill., knew the answer as well, but Sathwik got all five questions right in their one-on-one duel. Earlier, Conrad couldn't name Baotou as the largest city in China's Inner Mongolia Autonomous Region, which is home to one of the world's largest deposits of rare-earth elements. While Conrad didn't stumble again, Sathwik never relinquished the lead.
Sathwik and his brother said the victory was a team effort.
"It feels like I just finished something that he wanted to finish, so I sort of in a way completed his unfinished business," said Sathwik, who stands 4-foot-11 and has the fuzzy outline of a mustache on his upper lip.
Said Karthik: "I'm kind of elated now. What we started so many years ago has finally paid off."
Sathwik might have made it to the finals earlier if not for Karthik, who beat him twice in the Massachusetts state bee. But the younger brother triumphed at their school bee three years ago when he was in fourth grade and Karthik was in sixth, a moment Karthik described as "kind of a down point in my geography career."
Is Sathwik smarter?
"In some ways he is, in some ways he isn't," Karthik said. "The questions this year that they asked were of his liking, and that's the chief reason why he won."
The boys' mother, Rathma, and her husband, Vishwanath, who both work in the software industry, emigrated from near Mangalore, India, in 2002. Indian-American children have dominated both the National Geographic Bee and the Scripps National Spelling Bee in recent years. Vishwanath said the trend can be attributed to coming from a country of 1.2 billion people.
"That brought us the competitive spirit," he said. "If we don't work hard and put forth our best effort, we can't succeed in this world."
Ten participants made the finals, culled from a field of 54 state-level winners in Monday's preliminary round. Sathwik led throughout the final round and was the last contestant to get a question wrong.
Participants earned between 1 and 5 points for each correct answer, with the harder questions worth more points, and the competitors with the lowest scores were eliminated at various points in the competition.
Sathwik won a $25,000 scholarship, a trip to the Galapagos Islands and a lifetime membership in the National Geographic Society. The finals will be televised Thursday night on the National Geographic Channel and Nat Geo WILD.
Sathwik, an aspiring doctor who also plays chess competitively, said he was nervous at first because he had never been on television before, but he became more comfortable as he rattled off a string of correct answers.
Conrad, the runner-up, won a $15,000 scholarship. Ricky Uppaluri of Roswell, Ga., at 11 the youngest of the finalists, was third and receives a $10,000 scholarship. Akhil Rekulapelli of Ashburn, Va., finished fourth and won $1,000 in cash.
Sathwik said he buckled down once he realized he had a chance to win, because he didn't want to return to the bee next year. Children can compete from fourth to eighth grade, but winners are ineligible to defend their title.
"I didn't want to go back because it's just a lot of preparation and a lot of nervousness," he said. "I wanted to finish it this time."
"Jeopardy!" host Alex Trebek, who has moderated the bee finals since the inaugural competition in 1989, is stepping down after this year and will be replaced by broadcast journalist Soledad O'Brien.
During a commercial break, Trebek warned the audience at Washington's National Theatre not to blurt out or silently mouth the answers.
"As if that's likely to happen," he said to laughter. "Most of you can't even find Detroit."