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In 2-dimensional geometry, a lens is a biconvex (convex-convex) shape comprising two circular arcs, joined at their endpoints. A similar concave-convex shape is called a lune. If the arcs have equal radii, it is called a symmetric lens, otherwise is an asymmetric lens. The vesica piscis is one form of a symmetrical lens, formed by arcs of two circles whose centers each lie on the opposite arc. The arcs meet at angles of 120° at their endpoints. A lens can be seen as two circular segments, attached along their common chord. The area inside a symmetric lens can be defined by the radius ''R'' and arc lengths ''θ'' in radians: : A lens with a different shape forms part of the answer to Mrs. Miniver's problem, which asks how to bisect the area of a disk by an arc of another circle with given radius. One of the two areas into which the disk is bisected is a lens. Lenses are used to define beta skeletons, geometric graphs defined on a set of points by connecting pairs of points by an edge whenever a lens determined by the two points is empty. == References == * * * * 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Lens (geometry)」の詳細全文を読む スポンサード リンク
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