Spherical geometry other geometric concepts are defined as in plane geometry, but with straight lines replaced by great circles. Thus, in spherical geometry, angles are defined between great circles, resulting in a spherical trigonometry that differs from ordinary trigonometry in many respects; for example, the sum of the interior angles of a triangle exceeds 180 degrees. Spherical geometry is "not" elliptic geometry, but is rather a "subset" of elliptic geometry. For example, it shares with that geometry the property that a line has no parallels through a given point. Contrast this with Euclidean geometry, in which a line has one parallel through
OMB Circular A-126 specific aircraft, or Air Force-provided direct costs of operations. OMB Circular A-126 OMB Circular A-126, revised May 22, 1992, is a Government circular that introduces standards and policies to minimize the cost and improve the management and use of United States Government aircraft. Specifically, OMB Circular A-126 addresses the acquisition, management, usage, cost accounting, and disposal of government aircraft. All policies presented by this circular apply to Executive Agencies, with special policy covering the travel by senior officials or non-Federal travelers on government aircraft that is government-owned, leased, chartered or rented and any related services that apply. The only exceptions