Brasília (Portuguese pronunciation: [bɾaˈziljɐ]) is the federal capital of Brazil and seat of government of the Federal District. The city is located atop the Brazilian highlands in the country's center-western region. It was founded on April 21, 1960, to serve as the new national capital. Brasília and its metro (encompassing the whole of the Federal District) had a population of 2,556,149 in 2011, making it the 4th most populous city in Brazil. Among major Latin American cities, Brasília has the highest GDP per capita at R$61,915 (US$36,175).
Try to answer this question if possible (otherwise reply "unanswerable"): What is the population of Brasilia's Federal District?
unanswerable