<P> Stimson told U.S. President Franklin D. Roosevelt in May 1941 that the War Department needed additional space . On July 17, 1941, a congressional hearing took place, organized by Virginia congressman Clifton Woodrum, regarding proposals for new War Department buildings . Woodrum pressed Brigadier General Eugene Reybold, who was representing the War Department at the hearing, for an "overall solution" to the department's "space problem" rather than building yet more temporary buildings . Reybold agreed to report back to the congressman within five days . The War Department called upon its construction chief, General Brehon Somervell, to come up with a plan . </P> <P> Government officials agreed that the War Department building, officially designated Federal Office Building No 1, should be constructed across the Potomac River, in Arlington County, Virginia . Requirements for the new building were that it be no more than four stories tall, and that it use a minimal amount of steel . The requirements meant that, instead of rising vertically, the building would be sprawling over a large area . Possible sites for the building included the Department of Agriculture's Arlington Experimental Farm, adjacent to Arlington National Cemetery, and the obsolete Hoover Field site . </P> <P> The site originally chosen was Arlington Farms which had a roughly pentagonal shape, so the building was planned accordingly as an irregular pentagon . Concerned that the new building could obstruct the view of Washington, D.C., from Arlington Cemetery, President Roosevelt ended up selecting the Hoover Airport site instead . The building retained its pentagonal layout because a major redesign at that stage would have been costly, and Roosevelt liked the design . Freed of the constraints of the asymmetric Arlington Farms site, it was modified into a regular pentagon which resembled the star forts of the gunpowder age . </P> <P> On July 28 Congress authorized funding for a new Department of War building in Arlington, which would house the entire department under one roof, and President Roosevelt officially approved of the Hoover Airport site on September 2 . While the project went through the approval process in late July 1941, Somervell selected the contractors, including John McShain, Inc. of Philadelphia, which had built Washington National Airport in Arlington, the Jefferson Memorial in Washington, and the National Naval Medical Center in Bethesda, Maryland, along with Wise Contracting Company, Inc. and Doyle and Russell, both from Virginia . In addition to the Hoover Airport site and other government - owned land, construction of the Pentagon required an additional 287 acres (1.16 km), which were acquired at a cost of $2.2 million . The Hell's Bottom neighborhood, a slum with numerous pawnshops, factories, approximately 150 homes, and other buildings around Columbia Pike, was also cleared to make way for the Pentagon . Later 300 acres (1.2 km) of land were transferred to Arlington National Cemetery and to Fort Myer, leaving 280 acres (1.1 km) for the Pentagon . </P>

Why did they build the pentagon in that shape
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